2024-03-28T14:27:12Zhttp://repository.helmholtz-hzi.de/oai/requestoai:repository.helmholtz-hzi.de:10033/84012019-08-30T11:32:37Zcom_10033_6805com_10033_6799col_10033_6880
Zyxin Is not Colocalized with Vasodilator-stimulated Phosphoprotein (VASP) at Lamellipodial Tips and Exhibits Different Dynamics to Vinculin, Paxillin, and VASP in Focal AdhesionsV⃞
Rottner, Klemens
Krause, Matthias
Gimona, Mario
Small, J. Victor
Wehland, Jürgen
Beckerle, Mary C.
2007-02-14T15:43:39Z
2001-10
2007-02-14T15:43:39Z
2001-10
Molecular Biology of the Cell 2001 12(10):3103-3113
1059-1524
11598195
http://hdl.handle.net/10033/8401
60159
en_US
Copyright © 2001, The American Society for Cell Biology
The American Society for Cell Biology
oai:repository.helmholtz-hzi.de:10033/146022019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
The making of filopodia.
Faix, Jan
Rottner, Klemens
Filopodia are rod-like cell surface projections filled with bundles of parallel actin filaments. They are found on a variety of cell types and have been ascribed sensory or exploratory functions. Filopodium formation is frequently associated with protrusion of sheet-like actin filament arrays called lamellipodia and membrane ruffles, but, in comparison to these structures, the molecular details underpinning the initiation and maintenance of filopodia are only just beginning to emerge. Recent advances have improved our understanding of the molecular requirements for filopodium protrusion and have yielded insights into the inter-relationships between lamellipodia and filopodia, the two 'sub-compartments' of the protrusive actin cytoskeleton.
2007-11-16T15:25:43Z
2007-11-16T15:25:43Z
2006-02-01
Article
Curr. Opin. Cell Biol. 2006, 18(1):18-25
0955-0674
16337369
10.1016/j.ceb.2005.11.002
http://hdl.handle.net/10033/14602
en
oai:repository.helmholtz-hzi.de:10033/150922019-08-30T11:32:15Zcom_10033_6805com_10033_6799col_10033_6880
Live imaging of gliobastoma cells in brain tissue shows requirement of avtin bundles for migration
CASPANI, Elisabetta M.
Echevarria, Diego
Rottner, Klemens
Small, J. Victor
2007-12-10T10:25:34Z
2007-12-10T10:25:34Z
2006
2006
Article
Neuron Glia Biology, 2 (2), pp. 105-114.
1740925X
17410533
10.1017/S1740925X06000111
http://hdl.handle.net/10033/15092
Neuron Glia Biology
Cambridge University Press
oai:repository.helmholtz-hzi.de:10033/197572019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
Cdc42 and phosphoinositide 3-kinase drive Rac-mediated actin polymerization downstream of c-Met in distinct and common pathways.
Bosse, Tanja
Ehinger, Julia
Czuchra, Aleksandra
Benesch, Stefanie
Steffen, Anika
Wu, Xunwei
Schloen, Kathrin
Niemann, Hartmut H
Scita, Giorgio
Stradal, Theresia E B
Brakebusch, Cord
Rottner, Klemens
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, D-38124, Braunschweig, Germany.
Activation of c-Met, the hepatocyte growth factor (HGF)/scatter factor receptor induces reorganization of the actin cytoskeleton, which drives epithelial cell scattering and motility and is exploited by pathogenic Listeria monocytogenes to invade nonepithelial cells. However, the precise contributions of distinct Rho-GTPases, the phosphatidylinositol 3-kinases, and actin assembly regulators to c-Met-mediated actin reorganization are still elusive. Here we report that HGF-induced membrane ruffling and Listeria invasion mediated by the bacterial c-Met ligand internalin B (InlB) were significantly impaired but not abrogated upon genetic removal of either Cdc42 or pharmacological inhibition of phosphoinositide 3-kinase (PI3-kinase). While loss of Cdc42 or PI3-kinase function correlated with reduced HGF- and InlB-triggered Rac activation, complete abolishment of actin reorganization and Rac activation required the simultaneous inactivation of both Cdc42 and PI3-kinase signaling. Moreover, Cdc42 activation was fully independent of PI3-kinase activity, whereas the latter partly depended on Cdc42. Finally, Cdc42 function did not require its interaction with the actin nucleation-promoting factor N-WASP. Instead, actin polymerization was driven by Arp2/3 complex activation through the WAVE complex downstream of Rac. Together, our data establish an intricate signaling network comprising as key molecules Cdc42 and PI3-kinase, which converge on Rac-mediated actin reorganization essential for Listeria invasion and membrane ruffling downstream of c-Met.
2008-03-05T09:59:13Z
2008-03-05T09:59:13Z
2007-10
Article
Cdc42 and phosphoinositide 3-kinase drive Rac-mediated actin polymerization downstream of c-Met in distinct and common pathways. 2007, 27 (19):6615-28 Mol. Cell. Biol.
0270-7306
17682062
10.1128/MCB.00367-07
http://hdl.handle.net/10033/19757
Molecular and cellular biology
en
oai:repository.helmholtz-hzi.de:10033/224122019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
Arp2/3 complex interactions and actin network turnover in lamellipodia.
Lai, FP
Szczodrak, M
Block, J
Faix, J
Breitsprecher, D
Mannherz, HG
Stradal, TE
Dunn, GA
Small, JV
Rottner, K
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Cell migration is initiated by lamellipodia-membrane-enclosed sheets of cytoplasm containing densely packed actin filament networks. Although the molecular details of network turnover remain obscure, recent work points towards key roles in filament nucleation for Arp2/3 complex and its activator WAVE complex. Here, we combine fluorescence recovery after photobleaching (FRAP) of different lamellipodial components with a new method of data analysis to shed light on the dynamics of actin assembly/disassembly. We show that Arp2/3 complex is incorporated into the network exclusively at the lamellipodium tip, like actin, at sites coincident with WAVE complex accumulation. Capping protein likewise showed a turnover similar to actin and Arp2/3 complex, but was confined to the tip. In contrast, cortactin-another prominent Arp2/3 complex regulator-and ADF/cofilin-previously implicated in driving both filament nucleation and disassembly-were rapidly exchanged throughout the lamellipodium. These results suggest that Arp2/3- and WAVE complex-driven actin filament nucleation at the lamellipodium tip is uncoupled from the activities of both cortactin and cofilin. Network turnover is additionally regulated by the spatially segregated activities of capping protein at the tip and cofilin throughout the mesh.
2008-04-07T09:08:14Z
2008-04-07T09:08:14Z
2008-02-28
Article
Arp2/3 complex interactions and actin network turnover in lamellipodia. 2008: EMBO J.
1460-2075
18309290
10.1038/emboj.2008.34
http://hdl.handle.net/10033/22412
The EMBO journal
null
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18309290
oai:repository.helmholtz-hzi.de:10033/368122019-08-30T11:33:05Zcom_10033_6805com_10033_6799col_10033_6880
On the Rho'd: the regulation of membrane protrusions by Rho-GTPases.
Ladwein, Markus
Rottner, Klemens
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research (HZI), Inhoffen Strasse 7, D-38124 Braunschweig, Germany.
Cell migration entails the formation of cellular protrusions such as lamellipodia or filopodia, the growth of which is powered by the polymerisation of actin filaments abutting the plasma membrane. Specific Rho-GTPase subfamilies are able to drive different types of protrusions. However, significant crosstalk between Rho-family members and the interplay of distinct Rho-effectors regulating or modulating actin reorganization in protrusions complicate the picture of how precisely they are initiated and maintained. Here, we briefly sketch our current knowledge on structure and dynamics of different protrusions as well as their regulation by Rho-GTPases. We also comment on topical, unresolved controversies in the field, with special emphasis on the interrelation of different protrusion types, and on the composition of the nanomachineries driving them.
2008-08-29T08:49:47Z
2008-08-29T08:49:47Z
2008-06-18
Article
On the Rho'd: the regulation of membrane protrusions by Rho-GTPases. 2008, 582 (14):2066-74 FEBS Lett.
0014-5793
18442478
10.1016/j.febslet.2008.04.033
http://hdl.handle.net/10033/36812
FEBS letters
en
oai:repository.helmholtz-hzi.de:10033/482442019-08-30T11:30:58Zcom_10033_6805com_10033_6799col_10033_6880
Differentially oriented populations of actin filaments generated in lamellipodia collaborate in pushing and pausing at the cell front.
Koestler, Stefan A
Auinger, Sonja
Vinzenz, Marlene
Rottner, Klemens
Small, J Victor
Institute of Molecular Biotechnology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
Eukaryotic cells advance in phases of protrusion, pause and withdrawal. Protrusion occurs in lamellipodia, which are composed of diagonal networks of actin filaments, and withdrawal terminates with the formation of actin bundles parallel to the cell edge. Using correlated live-cell imaging and electron microscopy, we have shown that actin filaments in protruding lamellipodia subtend angles from 15-90 degrees to the front, and that transitions from protrusion to pause are associated with a proportional increase in filaments oriented more parallel to the cell edge. Microspike bundles of actin filaments also showed a wide angular distribution and correspondingly variable bilateral polymerization rates along the cell front. We propose that the angular shift of filaments in lamellipodia serves in adapting to slower protrusion rates while maintaining the filament densities required for structural support; further, we suggest that single filaments and microspike bundles contribute to the construction of the lamella behind and to the formation of the cell edge when protrusion ceases. Our findings provide an explanation for the variable turnover dynamics of actin filaments in lamellipodia observed by fluorescence speckle microscopy and are inconsistent with a current model of lamellipodia structure that features actin filaments branching at 70 degrees in a dendritic array.
2009-01-30T14:11:51Z
2009-01-30T14:11:51Z
2008-03
Article
Differentially oriented populations of actin filaments generated in lamellipodia collaborate in pushing and pausing at the cell front. 2008, 10 (3):306-13 Nat. Cell Biol.
1476-4679
18278037
10.1038/ncb1692
http://hdl.handle.net/10033/48244
Nature cell biology
en
oai:repository.helmholtz-hzi.de:10033/485432019-08-30T11:27:16Zcom_10033_6805com_10033_6799col_10033_6880
Filopodia formation induced by active mDia2/Drf3.
Block, J
Stradal, T E B
Hänisch, J
Geffers, Robert
Köstler, S A
Urban, E
Small, J V
Rottner, K
Faix, J
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Filopodia are rod-shaped cell surface protrusions composed of a parallel bundle of actin filaments. Since filopodia frequently emanate from lamellipodia, it has been proposed that they form exclusively by the convergence and elongation of actin filaments generated in lamellipodia networks. However, filopodia form without Arp2/3-complex, which is essential for lamellipodia formation, indicating that actin filaments in filopodia may be generated by other nucleators. Here we analyzed the effects of ectopic expression of GFP-tagged full length or a constitutively active variant of the human formin mDia2/Drf3. By contrast to the full-length molecule, which did not affect cell behaviour and was entirely cytosolic, active Drf3 lacking the C-terminal regulatory region (Drf3DeltaDAD) induced the formation of filopodia and accumulated at their tips. Low expression of Drf3DeltaDAD induced rod-shaped or tapered filopodia, whereas over-expression resulted in multiple, club-shaped filopodia. The clubs were filled with densely bundled actin filaments, whose number but not packing density decreased further away from the tip. Interestingly, clubs frequently increased in width after protrusion beyond the cell periphery, which correlated with increased amounts of Drf3DeltaDAD at their tips. These data suggest Drf3-induced filopodia form and extend by de novo nucleation of actin filaments instead of convergent elongation. Finally, Drf3DeltaDAD also induced the formation of unusual, lamellipodia-like structures, which contained both lamellipodial markers and the prominent filopodial protein fascin. Microarray analyses revealed highly variable Drf3 expression levels in different commonly used cell lines, reflecting the need for more detailed analyses of the functions of distinct formins in actin cytoskeleton turnover and different cell types.
2009-02-05T15:40:21Z
2009-02-05T15:40:21Z
2008-09
Article
Filopodia formation induced by active mDia2/Drf3. 2008, 231 (3):506-17notJ Microsc
1365-2818
18755006
10.1111/j.1365-2818.2008.02063.x
http://hdl.handle.net/10033/48543
Journal of microscopy
en
oai:repository.helmholtz-hzi.de:10033/705752019-08-30T11:33:29Zcom_10033_6805com_10033_6799col_10033_6880
F- and G-actin concentrations in lamellipodia of moving cells.
Koestler, Stefan A
Rottner, Klemens
Lai, Frank
Block, Jennifer
Vinzenz, Marlene
Small, J Victor
Institute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna, Austria.
Cells protrude by polymerizing monomeric (G) into polymeric (F) actin at the tip of the lamellipodium. Actin filaments are depolymerized towards the rear of the lamellipodium in a treadmilling process, thereby supplementing a G-actin pool for a new round of polymerization. In this scenario the concentrations of F- and G-actin are principal parameters, but have hitherto not been directly determined. By comparing fluorescence intensities of bleached and unbleached regions of lamellipodia in B16-F1 mouse melanoma cells expressing EGFP-actin, before and after extraction with Triton X-100, we show that the ratio of F- to G-actin is 3.2+/-0.9. Using electron microscopy to determine the F-actin content, this ratio translates into F- and G-actin concentrations in lamellipodia of approximately 500 microM and 150 microM, respectively. The excess of G-actin, at several orders of magnitude above the critical concentrations at filament ends indicates that the polymerization rate is not limited by diffusion and is tightly controlled by polymerization/depolymerization modulators.
2009-06-16T13:02:06Z
2009-06-16T13:02:06Z
2009
Article
F- and G-actin concentrations in lamellipodia of moving cells. 2009, 4 (3):e4810 PLoS ONE
1932-6203
19277198
10.1371/journal.pone.0004810
http://hdl.handle.net/10033/70575
PloS one
en
oai:repository.helmholtz-hzi.de:10033/770732019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
Filopodia: Complex models for simple rods.
Faix, Jan
Breitsprecher, Dennis
Stradal, Theresia E B
Rottner, Klemens
Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany. faix@bpc.mh-hannover.de
Filopodia are prominent cell surface projections filled with bundles of linear actin filaments that drive their protrusion. These structures are considered important sensory organelles, for instance in neuronal growth cones or during the fusion of sheets of epithelial tissues. In addition, they can serve a precursor function in adhesion site or stress fibre formation. Actin filament assembly is essential for filopodia formation and turnover, yet the precise molecular mechanisms of filament nucleation and/or elongation are controversial. Indeed, conflicting reports on the molecular requirements of filopodia initiation have prompted researchers to propose different types and/or alternative or redundant mechanisms mediating this process. However, recent data shed new light on these questions, and they indicate that the balance of a limited set of biochemical activities can determine the structural outcome of a given filopodium. Here we focus on discussing our current view of the relevance of these activities, and attempt to propose a molecular mechanism of filopodia assembly based on a single core machinery.
2009-08-12T13:07:50Z
2009-08-12T13:07:50Z
2009-08-12T13:07:50Z
Article
Filopodia: Complex models for simple rods., 41 (8-9):1656-64 Int. J. Biochem. Cell Biol.
1878-5875
19433307
10.1016/j.biocel.2009.02.012
http://hdl.handle.net/10033/77073
The international journal of biochemistry & cell biology
en
oai:repository.helmholtz-hzi.de:10033/847672019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions.
Himmel, Mirko
Ritter, Anett
Rothemund, Sven
Pauling, Björg V
Rottner, Klemens
Gingras, Alexandre R
Ziegler, Wolfgang H
Interdisciplinary Centre for Clinical Research (IZKF) Leipzig, Faculty of Medicine, University of Leipzig, D-04103 Leipzig, Germany.
In cell-extracellular matrix junctions (focal adhesions), the cytoskeletal protein talin is central to the connection of integrins to the actin cytoskeleton. Talin is thought to mediate this connection via its two integrin, (at least) three actin, and several vinculin binding sites. The binding sites are cryptic in the head-to-rod autoinhibited cytoplasmic form of the protein and require (stepwise) conformational activation. This activation process, however, remains poorly understood, and there are contradictory models with respect to the determinants of adhesion site localization. Here, we report turnover rates and protein-protein interactions in a range of talin rod domain constructs varying in helix bundle structure. We conclude that several bundles of the C terminus cooperate to regulate targeting and concomitantly tailor high affinity interactions of the talin rod in cell adhesions. Intrinsic control of ligand binding activities is essential for the coordination of adhesion site function of talin.
2009-10-23T14:02:31Z
2009-10-23T14:02:31Z
2009-05-15
Article
Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions. 2009, 284 (20):13832-42 J. Biol. Chem.
0021-9258
19278997
10.1074/jbc.M900266200
http://hdl.handle.net/10033/84767
The Journal of biological chemistry
en
oai:repository.helmholtz-hzi.de:10033/979792019-08-30T11:35:39Zcom_10033_6805com_10033_6799col_10033_6880
Molecular dissection of Salmonella-induced membrane ruffling versus invasion.
Hänisch, Jan
Ehinger, Julia
Ladwein, Markus
Rohde, Manfred
Derivery, Emmanuel
Bosse, Tanja
Steffen, Anika
Bumann, Dirk
Misselwitz, Benjamin
Hardt, Wolf-Dietrich
Gautreau, Alexis
Stradal, Theresia E B
Rottner, Klemens
Helmholtz Centre for Infection Research, Braunschweig, Germany.
Type III secretion system-mediated injection of a cocktail of bacterial proteins drives actin rearrangements, frequently adopting the shape of prominent protuberances of ruffling membrane, and culminating in host cell invasion of Gram-negative pathogens like Salmonella typhimurium. Different Salmonella effectors are able to bind actin and activate Rho-family GTPases, which have previously been implicated in mediating actin-dependent Salmonella entry by interacting with N-WASP or WAVE-complex, well-established activators of the actin nucleation machine Arp2/3-complex. Using genetic deletion and RNA interference studies, we show here that neither individual nor collective removal of these Arp2/3- complex activators affected host cell invasion as efficiently as Arp2/3-complex knock-down, although the latter was also not essential. However, interference with WAVE-complex function abrogated Salmonella-induced membrane ruffling without significantly affecting entry efficiency, actin or Arp2/3-complex accumulation. In addition, scanning electron microscopy images captured entry events in the absence of prominent membrane ruffles. Finally, localization and RNA interference studies indicated a relevant function in Salmonella entry for the novel Arp2/3-complex regulator WASH. These data establish for the first time that Salmonella invasion is separable from bacteria-induced membrane ruffling, and uncover an additional Arp2/3-complex activator as well as an Arp2/3-complex-independent actin assembly activity that contribute to Salmonella invasion.
2010-05-05T13:49:53Z
2010-05-05T13:49:53Z
2010-01
Article
Molecular dissection of Salmonella-induced membrane ruffling versus invasion. 2010, 12 (1):84-98 Cell. Microbiol.
1462-5822
19732055
10.1111/j.1462-5822.2009.01380.x
http://hdl.handle.net/10033/97979
Cellular microbiology
en
oai:repository.helmholtz-hzi.de:10033/1206292019-08-30T11:30:32Zcom_10033_6805com_10033_6799col_10033_6880
Molecular basis for the dual function of Eps8 on actin dynamics: bundling and capping.
Hertzog, Maud
Milanesi, Francesca
Hazelwood, Larnele
Disanza, Andrea
Liu, HongJun
Perlade, Emilie
Malabarba, Maria Grazia
Pasqualato, Sebastiano
Maiolica, Alessio
Confalonieri, Stefano
Le Clainche, Christophe
Offenhauser, Nina
Block, Jennifer
Rottner, Klemens
Di Fiore, Pier Paolo
Carlier, Marie-France
Volkmann, Niels
Hanein, Dorit
Scita, Giorgio
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy.
Actin capping and cross-linking proteins regulate the dynamics and architectures of different cellular protrusions. Eps8 is the founding member of a unique family of capping proteins capable of side-binding and bundling actin filaments. However, the structural basis through which Eps8 exerts these functions remains elusive. Here, we combined biochemical, molecular, and genetic approaches with electron microscopy and image analysis to dissect the molecular mechanism responsible for the distinct activities of Eps8. We propose that bundling activity of Eps8 is mainly mediated by a compact four helix bundle, which is contacting three actin subunits along the filament. The capping activity is mainly mediated by a amphipathic helix that binds within the hydrophobic pocket at the barbed ends of actin blocking further addition of actin monomers. Single-point mutagenesis validated these modes of binding, permitting us to dissect Eps8 capping from bundling activity in vitro. We further showed that the capping and bundling activities of Eps8 can be fully dissected in vivo, demonstrating the physiological relevance of the identified Eps8 structural/functional modules. Eps8 controls actin-based motility through its capping activity, while, as a bundler, is essential for proper intestinal morphogenesis of developing Caenorhabditis elegans.
2011-01-28T15:52:02Z
2011-01-28T15:52:02Z
2010
Article
Molecular basis for the dual function of Eps8 on actin dynamics: bundling and capping. 2010, 8 (6):e1000387 PLoS Biol.
1545-7885
20532239
10.1371/journal.pbio.1000387
http://hdl.handle.net/10033/120629
PLoS biology
en
oai:repository.helmholtz-hzi.de:10033/1210482019-08-30T11:36:05Zcom_10033_6805com_10033_6799col_10033_6880
The vinculin-DeltaIn20/21 mouse: characteristics of a constitutive, actin-binding deficient splice variant of vinculin.
Marg, Susanna
Winkler, Ulrike
Sestu, Marcello
Himmel, Mirko
Schönherr, Madeleine
Bär, Janina
Mann, Amrit
Moser, Markus
Mierke, Claudia T
Rottner, Klemens
Blessing, Manfred
Hirrlinger, Johannes
Ziegler, Wolfgang H
Faculty of Medicine, Interdisciplinary Centre for Clinical Research (IZKF) Leipzig, University of Leipzig, Leipzig, Germany.
The cytoskeletal adaptor protein vinculin plays a fundamental role in cell contact regulation and affects central aspects of cell motility, which are essential to both embryonal development and tissue homeostasis. Functional regulation of this evolutionarily conserved and ubiquitously expressed protein is dominated by a high-affinity, autoinhibitory head-to-tail interaction that spatially restricts ligand interactions to cell adhesion sites and, furthermore, limits the residency time of vinculin at these sites. To date, no mutants of the vinculin protein have been characterized in animal models.
2011-02-03T10:37:55Z
2011-02-03T10:37:55Z
2010
Article
The vinculin-DeltaIn20/21 mouse: characteristics of a constitutive, actin-binding deficient splice variant of vinculin. 2010, 5 (7):e11530 PLoS ONE
1932-6203
20644727
10.1371/journal.pone.0011530
http://hdl.handle.net/10033/121048
PloS one
en
oai:repository.helmholtz-hzi.de:10033/1369562019-08-30T11:37:00Zcom_10033_6805com_10033_6799col_10033_6880
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes.
Jackson, Ben
Peyrollier, Karine
Pedersen, Esben
Basse, Astrid
Karlsson, Richard
Wang, Zhipeng
Lefever, Tine
Ochsenbein, Alexandra M
Schmidt, Gudula
Aktories, Klaus
Stanley, Alanna
Quondamatteo, Fabio
Ladwein, Markus
Rottner, Klemens
van Hengel, Jolanda
Brakebusch, Cord
Biomedical Institute, BRIC, University of Copenhagen, 2200 Copenhagen, Denmark.
RhoA is a small guanosine-5'-triphosphatase (GTPase) suggested to be essential for cytokinesis, stress fiber formation, and epithelial cell-cell contacts. In skin, loss of RhoA was suggested to underlie pemphigus skin blistering. To analyze RhoA function in vivo, we generated mice with a keratinocyte-restricted deletion of the RhoA gene. Despite a severe reduction of cofilin and myosin light chain (MLC) phosphorylation, these mice showed normal skin development. Primary RhoA-null keratinocytes, however, displayed an increased percentage of multinucleated cells, defective maturation of cell-cell contacts. Furthermore we observed increased cell spreading due to impaired RhoA-ROCK (Rho-associated protein kinase)-MLC phosphatase-MLC-mediated cell contraction, independent of Rac1. Rho-inhibiting toxins further increased multinucleation of RhoA-null cells but had no significant effect on spreading, suggesting that RhoB and RhoC have partially overlapping functions with RhoA. Loss of RhoA decreased directed cell migration in vitro caused by reduced migration speed and directional persistence. These defects were not related to the decreased cell contraction and were independent of ROCK, as ROCK inhibition by Y27632 increased directed migration of both control and RhoA-null keratinocytes. Our data indicate a crucial role for RhoA and contraction in regulating cell spreading and a contraction-independent function of RhoA in keratinocyte migration. In addition, our data show that RhoA is dispensable for skin development.
2011-07-26T10:22:10Z
2011-07-26T10:22:10Z
2011-03
Article
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes. 2011, 22 (5):593-605 Mol. Biol. Cell
1939-4586
21209320
10.1091/mbc.E09-10-0859
http://hdl.handle.net/10033/136956
Molecular biology of the cell
en
oai:repository.helmholtz-hzi.de:10033/1326092019-08-30T11:27:44Zcom_10033_6805com_10033_6799col_10033_6880
Introduction to Small GTPases
Williams, Michael J.
Rottner, Klemens
Helmholtz Center for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
2011-06-06T09:44:56Z
2011-06-06T09:44:56Z
2010-07
Article
Introduction to Small GTPases 2010, 1 (1):1 Small GTPases
2154-1248
10.4161/sgtp.1.1.12245
http://hdl.handle.net/10033/132609
Small GTPases
http://www.landesbioscience.com/journals/smallgtpases/article/12245/
oai:repository.helmholtz-hzi.de:10033/2138112019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes.
Jackson, Ben
Peyrollier, Karine
Pedersen, Esben
Basse, Astrid
Karlsson, Richard
Wang, Zhipeng
Lefever, Tine
Ochsenbein, Alexandra M
Schmidt, Gudula
Aktories, Klaus
Stanley, Alanna
Quondamatteo, Fabio
Ladwein, Markus
Rottner, Klemens
van Hengel, Jolanda
Brakebusch, Cord
Biomedical Institute, BRIC, University of Copenhagen, 2200 Copenhagen, Denmark.
RhoA is a small guanosine-5'-triphosphatase (GTPase) suggested to be essential for cytokinesis, stress fiber formation, and epithelial cell-cell contacts. In skin, loss of RhoA was suggested to underlie pemphigus skin blistering. To analyze RhoA function in vivo, we generated mice with a keratinocyte-restricted deletion of the RhoA gene. Despite a severe reduction of cofilin and myosin light chain (MLC) phosphorylation, these mice showed normal skin development. Primary RhoA-null keratinocytes, however, displayed an increased percentage of multinucleated cells, defective maturation of cell-cell contacts. Furthermore we observed increased cell spreading due to impaired RhoA-ROCK (Rho-associated protein kinase)-MLC phosphatase-MLC-mediated cell contraction, independent of Rac1. Rho-inhibiting toxins further increased multinucleation of RhoA-null cells but had no significant effect on spreading, suggesting that RhoB and RhoC have partially overlapping functions with RhoA. Loss of RhoA decreased directed cell migration in vitro caused by reduced migration speed and directional persistence. These defects were not related to the decreased cell contraction and were independent of ROCK, as ROCK inhibition by Y27632 increased directed migration of both control and RhoA-null keratinocytes. Our data indicate a crucial role for RhoA and contraction in regulating cell spreading and a contraction-independent function of RhoA in keratinocyte migration. In addition, our data show that RhoA is dispensable for skin development.
2012-03-01T16:01:13Z
2012-03-01T16:01:13Z
2011-03
Article
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes. 2011, 22 (5):593-605 Mol. Biol. Cell
1939-4586
21209320
10.1091/mbc.E09-10-0859
http://hdl.handle.net/10033/213811
Molecular biology of the cell
en
oai:repository.helmholtz-hzi.de:10033/2094532021-08-04T14:12:49Zcom_10033_6805com_10033_6799col_10033_6880
Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo.
Schnoor, Michael
Lai, Frank P L
Zarbock, Alexander
Kläver, Ruth
Polaschegg, Christian
Schulte, Dörte
Weich, Herbert A
Oelkers, J Margit
Rottner, Klemens
Vestweber, Dietmar
Max Planck Institute for Molecular Biomedicine, D 48149 Münster, Germany.
Neutrophil extravasation and the regulation of vascular permeability require dynamic actin rearrangements in the endothelium. In this study, we analyzed in vivo whether these processes require the function of the actin nucleation-promoting factor cortactin. Basal vascular permeability for high molecular weight substances was enhanced in cortactin-deficient mice. Despite this leakiness, neutrophil extravasation in the tumor necrosis factor-stimulated cremaster was inhibited by the loss of cortactin. The permeability defect was caused by reduced levels of activated Rap1 (Ras-related protein 1) in endothelial cells and could be rescued by activating Rap1 via the guanosine triphosphatase (GTPase) exchange factor EPAC (exchange protein directly activated by cAMP). The defect in neutrophil extravasation was caused by enhanced rolling velocity and reduced adhesion in postcapillary venules. Impaired rolling interactions were linked to contributions of β(2)-integrin ligands, and firm adhesion was compromised by reduced ICAM-1 (intercellular adhesion molecule 1) clustering around neutrophils. A signaling process known to be critical for the formation of ICAM-1-enriched contact areas and for transendothelial migration, the ICAM-1-mediated activation of the GTPase RhoG was blocked in cortactin-deficient endothelial cells. Our results represent the first physiological evidence that cortactin is crucial for orchestrating the molecular events leading to proper endothelial barrier function and leukocyte recruitment in vivo.
2012-02-06T14:40:51Z
2012-02-06T14:40:51Z
2011-08-01
Article
Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo. 2011, 208 (8):1721-35 J. Exp. Med.
1540-9538
21788407
10.1084/jem.20101920
http://hdl.handle.net/10033/209453
The Journal of experimental medicine
en
oai:repository.helmholtz-hzi.de:10033/3025012019-08-30T11:36:59Zcom_10033_6805com_10033_6799col_10033_6880
Cytotoxic necrotizing factor-y boosts yersinia effector translocation by activating rac protein.
Wolters, Manuel
Boyle, Erin C
Lardong, Kerstin
Trülzsch, Konrad
Steffen, Anika
Rottner, Klemens
Ruckdeschel, Klaus
Aepfelbacher, Martin
From the Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
Pathogenic Yersinia spp. translocate the effectors YopT, YopE, and YopO/YpkA into target cells to inactivate Rho family GTP-binding proteins and block immune responses. Some Yersinia spp. also secrete the Rho protein activator cytotoxic necrotizing factor-Y (CNF-Y), but it has been unclear how the bacteria may benefit from Rho protein activation. We show here that CNF-Y increases Yop translocation in Yersinia enterocolitica-infected cells up to 5-fold. CNF-Y strongly activated RhoA and also delayed in time Rac1 and Cdc42, but when individually expressed, constitutively active mutants of Rac1, but not of RhoA, increased Yop translocation. Consistently, knock-out or knockdown of Rac1 but not of RhoA, -B, or -C inhibited Yersinia effector translocation in CNF-Y-treated and control cells. Activation or knockdown of Cdc42 also affected Yop translocation but much less efficiently than Rac. The increase in Yop translocation induced by CNF-Y was essentially independent of the presence of YopE, YopT, or YopO in the infecting Yersinia strain, indicating that none of the Yops reported to inhibit translocation could reverse the CNF-Y effect. In summary, the CNF-Y activity of Yersinia strongly enhances Yop translocation through activation of Rac.
2013-09-30T08:44:15Z
2013-09-30T08:44:15Z
2013-08-09
Article
Cytotoxic necrotizing factor-y boosts yersinia effector translocation by activating rac protein. 2013, 288 (32):23543-53 J. Biol. Chem.
1083-351X
23803609
10.1074/jbc.M112.448662
http://hdl.handle.net/10033/302501
The Journal of biological chemistry
en
Archived with thanks to The Journal of biological chemistry
oai:repository.helmholtz-hzi.de:10033/3046022019-08-30T11:37:00Zcom_10033_6805com_10033_6799col_10033_6880
Arp2/3 complex is essential for actin network treadmilling as well as for targeting of capping protein and cofilin.
Koestler, Stefan A
Steffen, Anika
Nemethova, Maria
Winterhoff, Moritz
Luo, Ningning
Holleboom, J Margit
Krupp, Jessica
Jacob, Sonja
Vinzenz, Marlene
Schur, Florian
Schlüter, Kai
Gunning, Peter W
Winkler, Christoph
Schmeiser, Christian
Faix, Jan
Stradal, Theresia E B
Small, J Victor
Rottner, Klemens
Institute of Genetics, University of Bonn, D-53115 Bonn, Germany Institute of Molecular Biotechnology, Austrian Academy of Sciences, A-1030 Vienna, Austria Johann Radon Institute for Computational and Applied Mathematics, Austrian Academy of Sciences, A-1030 Vienna, Austria Institute for Biophysical Chemistry, Hannover Medical School, D-30625 Hannover, Germany Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany Institute for Molecular Cell Biology, University of Münster, D-48149 Münster, Germany Oncology Research Unit, School of Medical Sciences, University of New South Wales, Sydney 2052, Australia Faculty of Mathematics, University of Vienna, A-1090 Vienna, Austria.
Lamellipodia are sheet-like protrusions formed during migration or phagocytosis and comprise a network of actin filaments. Filament formation in this network is initiated by nucleation/branching through the actin-related protein 2/3 (Arp2/3) complex downstream of its activator, suppressor of cAMP receptor/WASP-family verprolin homologous (Scar/WAVE), but the relative relevance of Arp2/3-mediated branching versus actin filament elongation is unknown. Here we use instantaneous interference with Arp2/3 complex function in live fibroblasts with established lamellipodia. This allows direct examination of both the fate of elongating filaments upon instantaneous suppression of Arp2/3 complex activity and the consequences of this treatment on the dynamics of other lamellipodial regulators. We show that Arp2/3 complex is an essential organizer of treadmilling actin filament arrays but has little effect on the net rate of actin filament turnover at the cell periphery. In addition, Arp2/3 complex serves as key upstream factor for the recruitment of modulators of lamellipodia formation such as capping protein or cofilin. Arp2/3 complex is thus decisive for filament organization and geometry within the network not only by generating branches and novel filament ends, but also by directing capping or severing activities to the lamellipodium. Arp2/3 complex is also crucial to lamellipodia-based migration of keratocytes.
2013-10-24T14:19:15Z
2013-10-24T14:19:15Z
2013-09
Article
Arp2/3 complex is essential for actin network treadmilling as well as for targeting of capping protein and cofilin. 2013, 24 (18):2861-75 Mol. Biol. Cell
1939-4586
23885122
10.1091/mbc.E12-12-0857
http://hdl.handle.net/10033/304602
Molecular biology of the cell
en
Archived with thanks to Molecular biology of the cell
oai:repository.helmholtz-hzi.de:10033/3061702019-08-30T11:25:11Zcom_10033_6805com_10033_6799col_10033_6880
Rac function is crucial for cell migration but is not required for spreading and focal adhesion formation.
Steffen, Anika
Ladwein, Markus
Dimchev, Georgi A
Hein, Anke
Schwenkmezger, Lisa
Arens, Stefan
Ladwein, Kathrin I
Margit Holleboom, J
Schur, Florian
Victor Small, J
Schwarz, Janett
Gerhard, Ralf
Faix, Jan
Stradal, Theresia E B
Brakebusch, Cord
Rottner, Klemens
Institute of Genetics, University of Bonn, Karlrobert-Kreiten Strasse 13, D-53115 Bonn, Germany.
Cell migration is commonly accompanied by protrusion of membrane ruffles and lamellipodia. In two-dimensional migration, protrusion of these thin sheets of cytoplasm is considered relevant to both exploration of new space and initiation of nascent adhesion to the substratum. Lamellipodium formation can be potently stimulated by Rho GTPases of the Rac subfamily, but also by RhoG or Cdc42. Here we describe viable fibroblast cell lines genetically deficient for Rac1 that lack detectable levels of Rac2 and Rac3. Rac-deficient cells were devoid of apparent lamellipodia, but these structures were restored by expression of either Rac subfamily member, but not by Cdc42 or RhoG. Cells deficient in Rac showed strong reduction in wound closure and random cell migration and a notable loss of sensitivity to a chemotactic gradient. Despite these defects, Rac-deficient cells were able to spread, formed filopodia and established focal adhesions. Spreading in these cells was achieved by the extension of filopodia followed by the advancement of cytoplasmic veils between them. The number and size of focal adhesions as well as their intensity were largely unaffected by genetic removal of Rac1. However, Rac deficiency increased the mobility of different components in focal adhesions, potentially explaining how Rac - although not essential - can contribute to focal adhesion assembly. Together, our data demonstrate that Rac signaling is essential for lamellipodium protrusion and for efficient cell migration, but not for spreading or filopodium formation. Our findings also suggest that Rac GTPases are crucial to the establishment or maintenance of polarity in chemotactic migration.
2013-12-03T15:16:23Z
2013-12-03T15:16:23Z
2013-10-15
Article
Rac function is crucial for cell migration but is not required for spreading and focal adhesion formation. 2013, 126 (Pt 20):4572-88 J. Cell. Sci.
1477-9137
23902686
10.1242/jcs.118232
http://hdl.handle.net/10033/306170
Journal of cell science
en
Archived with thanks to Journal of cell science