2.50
Hdl Handle:
http://hdl.handle.net/10033/52193
Title:
Structural and functional characterization of human Iba proteins.
Authors:
Schulze, Jörg O; Quedenau, Claudia; Roske, Yvette; Adam, Thomas; Schüler, Herwig; Behlke, Joachim; Turnbull, Andrew P; Sievert, Volker; Scheich, Christoph; Mueller, Uwe; Heinemann, Udo; Büssow, Konrad ( 0000-0003-2031-5942 )
Abstract:
Iba2 is a homolog of ionized calcium-binding adapter molecule 1 (Iba1), a 17-kDa protein that binds and cross-links filamentous actin (F-actin) and localizes to membrane ruffles and phagocytic cups. Here, we present the crystal structure of human Iba2 and its homodimerization properties, F-actin cross-linking activity, cellular localization and recruitment upon bacterial invasion in comparison with Iba1. The Iba2 structure comprises two central EF-hand motifs lacking bound Ca2+. Iba2 crystallized as a homodimer stabilized by a disulfide bridge and zinc ions. Analytical ultracentrifugation revealed a different mode of dimerization under reducing conditions that was independent of Ca2+. Furthermore, no binding of Ca2+ up to 0.1 mM was detected by equilibrium dialysis. Correspondingly, Iba EF-hand motifs lack residues essential for strong Ca2+ coordination. Sedimentation experiments and microscopy detected pronounced, indistinguishable F-actin binding and cross-linking activity of Iba1 and Iba2 with induction of F-actin bundles. Fluorescent Iba fusion proteins were expressed in HeLa cells and co-localized with F-actin. Iba1 was recruited into cellular projections to a larger extent than Iba2. Additionally, we studied Iba recruitment in a Shigella invasion model that induces cytoskeletal rearrangements. Both proteins were recruited into the bacterial invasion zone and Iba1 was again concentrated slightly higher in the cellular extensions.
Affiliation:
Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Citation:
Structural and functional characterization of human Iba proteins. 2008, 275 (18):4627-40 FEBS J.
Journal:
The FEBS journal
Issue Date:
Sep-2008
URI:
http://hdl.handle.net/10033/52193
DOI:
10.1111/j.1742-4658.2008.06605.x
PubMed ID:
18699778
Type:
Article
Language:
en
ISSN:
1742-464X
Appears in Collections:
publications of the research group vaccinology and applied microbiology (VAC)

Full metadata record

DC FieldValue Language
dc.contributor.authorSchulze, Jörg Oen
dc.contributor.authorQuedenau, Claudiaen
dc.contributor.authorRoske, Yvetteen
dc.contributor.authorAdam, Thomasen
dc.contributor.authorSchüler, Herwigen
dc.contributor.authorBehlke, Joachimen
dc.contributor.authorTurnbull, Andrew Pen
dc.contributor.authorSievert, Volkeren
dc.contributor.authorScheich, Christophen
dc.contributor.authorMueller, Uween
dc.contributor.authorHeinemann, Udoen
dc.contributor.authorBüssow, Konraden
dc.date.accessioned2009-03-05T09:01:48Zen
dc.date.available2009-03-05T09:01:48Zen
dc.date.issued2008-09en
dc.identifier.citationStructural and functional characterization of human Iba proteins. 2008, 275 (18):4627-40 FEBS J.en
dc.identifier.issn1742-464Xen
dc.identifier.pmid18699778en
dc.identifier.doi10.1111/j.1742-4658.2008.06605.xen
dc.identifier.urihttp://hdl.handle.net/10033/52193en
dc.description.abstractIba2 is a homolog of ionized calcium-binding adapter molecule 1 (Iba1), a 17-kDa protein that binds and cross-links filamentous actin (F-actin) and localizes to membrane ruffles and phagocytic cups. Here, we present the crystal structure of human Iba2 and its homodimerization properties, F-actin cross-linking activity, cellular localization and recruitment upon bacterial invasion in comparison with Iba1. The Iba2 structure comprises two central EF-hand motifs lacking bound Ca2+. Iba2 crystallized as a homodimer stabilized by a disulfide bridge and zinc ions. Analytical ultracentrifugation revealed a different mode of dimerization under reducing conditions that was independent of Ca2+. Furthermore, no binding of Ca2+ up to 0.1 mM was detected by equilibrium dialysis. Correspondingly, Iba EF-hand motifs lack residues essential for strong Ca2+ coordination. Sedimentation experiments and microscopy detected pronounced, indistinguishable F-actin binding and cross-linking activity of Iba1 and Iba2 with induction of F-actin bundles. Fluorescent Iba fusion proteins were expressed in HeLa cells and co-localized with F-actin. Iba1 was recruited into cellular projections to a larger extent than Iba2. Additionally, we studied Iba recruitment in a Shigella invasion model that induces cytoskeletal rearrangements. Both proteins were recruited into the bacterial invasion zone and Iba1 was again concentrated slightly higher in the cellular extensions.en
dc.language.isoenen
dc.subject.meshActinsen
dc.subject.meshAmino Acid Sequenceen
dc.subject.meshCalciumen
dc.subject.meshCalcium-Binding Proteinsen
dc.subject.meshCrystallography, X-Rayen
dc.subject.meshDNA-Binding Proteinsen
dc.subject.meshDimerizationen
dc.subject.meshHela Cellsen
dc.subject.meshHumansen
dc.subject.meshMicrofilament Proteinsen
dc.subject.meshModels, Molecularen
dc.subject.meshMolecular Sequence Dataen
dc.subject.meshSequence Alignmenten
dc.subject.meshShigellaen
dc.titleStructural and functional characterization of human Iba proteins.en
dc.typeArticleen
dc.contributor.departmentMax Delbrück Center for Molecular Medicine, Berlin, Germany.en
dc.identifier.journalThe FEBS journalen

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