2.50
Hdl Handle:
http://hdl.handle.net/10033/346528
Title:
Oligomerization inhibits Legionella pneumophila PlaB phospholipase A activity.
Authors:
Kuhle, Katja; Krausze, Joern; Curth, Ute; Rössle, Manfred; Heuner, Klaus; Lang, Christina; Flieger, Antje
Abstract:
The intracellularly replicating lung pathogen Legionella pneumophila consists of an extraordinary variety of phospholipases, including at least 15 different phospholipases A (PLA). Among them, PlaB, the first characterized member of a novel lipase family, is a hemolytic virulence factor that exhibits the most prominent PLA activity in L. pneumophila. We analyzed here protein oligomerization, the importance of oligomerization for activity, addressed further essential regions for activity within the PlaB C terminus, and the significance of PlaB-derived lipolytic activity for L. pneumophila intracellular replication. We determined by means of analytical ultracentrifugation and small angle x-ray scattering analysis that PlaB forms homodimers and homotetramers. The C-terminal 5, 10, or 15 amino acids, although the individual regions contributed to PLA activity, were not essential for protein tetramerization. Infection of mouse macrophages with L. pneumophila wild type, plaB knock-out mutant, and plaB complementing or various mutated plaB-harboring strains showed that catalytic activity of PlaB promotes intracellular replication. We observed that PlaB was most active in the lower nanomolar concentration range but not at or only at a low level at concentration above 0.1 μm where it exists in a dimer/tetramer equilibrium. We therefore conclude that PlaB is a virulence factor that, on the one hand, assembles in inactive tetramers at micromolar concentrations. On the other hand, oligomer dissociation at nanomolar concentrations activates PLA activity. Our data highlight the first example of concentration-dependent phospholipase inactivation by tetramerization, which may protect the bacterium from internal PLA activity, but enzyme dissociation may allow its activation after export.
Citation:
Oligomerization inhibits Legionella pneumophila PlaB phospholipase A activity. 2014, 289 (27):18657-66 J. Biol. Chem.
Journal:
The Journal of biological chemistry
Issue Date:
4-Jul-2014
URI:
http://hdl.handle.net/10033/346528
DOI:
10.1074/jbc.M114.573196
PubMed ID:
24811180
Type:
Article
Language:
en
ISSN:
1083-351X
Appears in Collections:
Publications of the Dept. Structure and Functions of Proteins(SFPR)

Full metadata record

DC FieldValue Language
dc.contributor.authorKuhle, Katjaen
dc.contributor.authorKrausze, Joernen
dc.contributor.authorCurth, Uteen
dc.contributor.authorRössle, Manfreden
dc.contributor.authorHeuner, Klausen
dc.contributor.authorLang, Christinaen
dc.contributor.authorFlieger, Antjeen
dc.date.accessioned2015-03-11T14:54:36Zen
dc.date.available2015-03-11T14:54:36Zen
dc.date.issued2014-07-04en
dc.identifier.citationOligomerization inhibits Legionella pneumophila PlaB phospholipase A activity. 2014, 289 (27):18657-66 J. Biol. Chem.en
dc.identifier.issn1083-351Xen
dc.identifier.pmid24811180en
dc.identifier.doi10.1074/jbc.M114.573196en
dc.identifier.urihttp://hdl.handle.net/10033/346528en
dc.description.abstractThe intracellularly replicating lung pathogen Legionella pneumophila consists of an extraordinary variety of phospholipases, including at least 15 different phospholipases A (PLA). Among them, PlaB, the first characterized member of a novel lipase family, is a hemolytic virulence factor that exhibits the most prominent PLA activity in L. pneumophila. We analyzed here protein oligomerization, the importance of oligomerization for activity, addressed further essential regions for activity within the PlaB C terminus, and the significance of PlaB-derived lipolytic activity for L. pneumophila intracellular replication. We determined by means of analytical ultracentrifugation and small angle x-ray scattering analysis that PlaB forms homodimers and homotetramers. The C-terminal 5, 10, or 15 amino acids, although the individual regions contributed to PLA activity, were not essential for protein tetramerization. Infection of mouse macrophages with L. pneumophila wild type, plaB knock-out mutant, and plaB complementing or various mutated plaB-harboring strains showed that catalytic activity of PlaB promotes intracellular replication. We observed that PlaB was most active in the lower nanomolar concentration range but not at or only at a low level at concentration above 0.1 μm where it exists in a dimer/tetramer equilibrium. We therefore conclude that PlaB is a virulence factor that, on the one hand, assembles in inactive tetramers at micromolar concentrations. On the other hand, oligomer dissociation at nanomolar concentrations activates PLA activity. Our data highlight the first example of concentration-dependent phospholipase inactivation by tetramerization, which may protect the bacterium from internal PLA activity, but enzyme dissociation may allow its activation after export.en
dc.language.isoenen
dc.subject.meshAnimalsen
dc.subject.meshBiocatalysisen
dc.subject.meshCell Lineen
dc.subject.meshIntracellular Spaceen
dc.subject.meshLegionella pneumophilaen
dc.subject.meshLipolysisen
dc.subject.meshMacrophagesen
dc.subject.meshMiceen
dc.subject.meshModels, Molecularen
dc.subject.meshPhospholipasesen
dc.subject.meshProtein Multimerizationen
dc.subject.meshProtein Structure, Quaternaryen
dc.titleOligomerization inhibits Legionella pneumophila PlaB phospholipase A activity.en
dc.typeArticleen
dc.identifier.journalThe Journal of biological chemistryen

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