3su8: Difference between revisions
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3su8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3su8 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3su8 RCSB], [http://www.ebi.ac.uk/pdbsum/3su8 PDBsum]</span></td></tr> | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3su8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3su8 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3su8 RCSB], [http://www.ebi.ac.uk/pdbsum/3su8 PDBsum]</span></td></tr> | ||
</table> | </table> | ||
== Function == | |||
[[http://www.uniprot.org/uniprot/RAC1_HUMAN RAC1_HUMAN]] Plasma membrane-associated small GTPase which cycles between active GTP-bound and inactive GDP-bound states. In its active state, binds to a variety of effector proteins to regulate cellular responses such as secretory processes, phagocytosis of apoptotic cells, epithelial cell polarization and growth-factor induced formation of membrane ruffles. Rac1 p21/rho GDI heterodimer is the active component of the cytosolic factor sigma 1, which is involved in stimulation of the NADPH oxidase activity in macrophages (By similarity). Essential for the SPATA13-mediated regulation of cell migration and adhesion assembly and disassembly. Stimulates PKN2 kinase activity. In concert with RAB7A, plays a role in regulating the formation of RBs (ruffled borders) in osteoclasts. In glioma cells, promotes cell migration and invasion.<ref>PMID:1643658</ref> <ref>PMID:9121475</ref> <ref>PMID:19934221</ref> <ref>PMID:19403692</ref> <ref>PMID:20696765</ref> Isoform B has an accelerated GEF-independent GDP/GTP exchange and an impaired GTP hydrolysis, which is restored partially by GTPase-activating proteins. It is able to bind to the GTPase-binding domain of PAK but not full-length PAK in a GTP-dependent manner, suggesting that the insertion does not completely abolish effector interaction.<ref>PMID:1643658</ref> <ref>PMID:9121475</ref> <ref>PMID:19934221</ref> <ref>PMID:19403692</ref> <ref>PMID:20696765</ref> [[http://www.uniprot.org/uniprot/PLXB1_HUMAN PLXB1_HUMAN]] Receptor for SEMA4D. Plays a role in RHOA activation and subsequent changes of the actin cytoskeleton. Plays a role in axon guidance, invasive growth and cell migration.<ref>PMID:12198496</ref> <ref>PMID:12196628</ref> <ref>PMID:15210733</ref> <ref>PMID:19843518</ref> <ref>PMID:20877282</ref> <ref>PMID:21912513</ref> | |||
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== Publication Abstract from PubMed == | == Publication Abstract from PubMed == |
Revision as of 00:43, 26 December 2014
Crystal structure of a truncated intracellular domain of Plexin-B1 in complex with Rac1Crystal structure of a truncated intracellular domain of Plexin-B1 in complex with Rac1
Structural highlights
Function[RAC1_HUMAN] Plasma membrane-associated small GTPase which cycles between active GTP-bound and inactive GDP-bound states. In its active state, binds to a variety of effector proteins to regulate cellular responses such as secretory processes, phagocytosis of apoptotic cells, epithelial cell polarization and growth-factor induced formation of membrane ruffles. Rac1 p21/rho GDI heterodimer is the active component of the cytosolic factor sigma 1, which is involved in stimulation of the NADPH oxidase activity in macrophages (By similarity). Essential for the SPATA13-mediated regulation of cell migration and adhesion assembly and disassembly. Stimulates PKN2 kinase activity. In concert with RAB7A, plays a role in regulating the formation of RBs (ruffled borders) in osteoclasts. In glioma cells, promotes cell migration and invasion.[1] [2] [3] [4] [5] Isoform B has an accelerated GEF-independent GDP/GTP exchange and an impaired GTP hydrolysis, which is restored partially by GTPase-activating proteins. It is able to bind to the GTPase-binding domain of PAK but not full-length PAK in a GTP-dependent manner, suggesting that the insertion does not completely abolish effector interaction.[6] [7] [8] [9] [10] [PLXB1_HUMAN] Receptor for SEMA4D. Plays a role in RHOA activation and subsequent changes of the actin cytoskeleton. Plays a role in axon guidance, invasive growth and cell migration.[11] [12] [13] [14] [15] [16] Publication Abstract from PubMedPlexins are cell surface receptors for the semaphorin family of cell guidance cues. The cytoplasmic region comprises a Ras GTPase-activating protein (GAP) domain and a RhoGTPase binding domain. Concomitant binding of extracellular semaphorin and intracellular RhoGTPase triggers GAP activity and signal transduction. The mechanism of this intricate regulation remains elusive. We present two crystal structures of the human Plexin-B1 cytoplasmic region in complex with a constitutively active RhoGTPase, Rac1. The structure of truncated Plexin-B1-Rac1 complex provides no mechanism for coupling RhoGTPase and Ras binding sites. On inclusion of the juxtamembrane helix, a trimeric structure of Plexin-B1-Rac1 complexes is stabilised by a second, novel, RhoGTPase binding site adjacent to the Ras site. Site-directed mutagenesis combined with cellular and biophysical assays demonstrate that this new binding site is essential for signalling. Our findings are consistent with a model in which extracellular and intracellular plexin clustering events combine into a single signalling output. A Dual Binding Mode for RhoGTPases in Plexin Signalling.,Bell CH, Aricescu AR, Jones EY, Siebold C PLoS Biol. 2011 Aug;9(8):e1001134. Epub 2011 Aug 30. PMID:21912513[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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