| Structural highlights
3sua is a 6 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , |
| Related: | 3su8 |
| Gene: | RAC1, TC25, MIG5 (Homo sapiens), PLXNB1, KIAA0407, PLXN5, SEP (Homo sapiens) |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
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 PubMed
Plexins 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 Also
References
- ↑ Ridley AJ, Paterson HF, Johnston CL, Diekmann D, Hall A. The small GTP-binding protein rac regulates growth factor-induced membrane ruffling. Cell. 1992 Aug 7;70(3):401-10. PMID:1643658
- ↑ Vincent S, Settleman J. The PRK2 kinase is a potential effector target of both Rho and Rac GTPases and regulates actin cytoskeletal organization. Mol Cell Biol. 1997 Apr;17(4):2247-56. PMID:9121475
- ↑ Bristow JM, Sellers MH, Majumdar D, Anderson B, Hu L, Webb DJ. The Rho-family GEF Asef2 activates Rac to modulate adhesion and actin dynamics and thereby regulate cell migration. J Cell Sci. 2009 Dec 15;122(Pt 24):4535-46. doi: 10.1242/jcs.053728. Epub 2009, Nov 24. PMID:19934221 doi:10.1242/jcs.053728
- ↑ Hamill KJ, Hopkinson SB, DeBiase P, Jones JC. BPAG1e maintains keratinocyte polarity through beta4 integrin-mediated modulation of Rac1 and cofilin activities. Mol Biol Cell. 2009 Jun;20(12):2954-62. doi: 10.1091/mbc.E09-01-0051. Epub 2009, Apr 29. PMID:19403692 doi:10.1091/mbc.E09-01-0051
- ↑ Li X, Lee AY. Semaphorin 5A and plexin-B3 inhibit human glioma cell motility through RhoGDIalpha-mediated inactivation of Rac1 GTPase. J Biol Chem. 2010 Oct 15;285(42):32436-45. doi: 10.1074/jbc.M110.120451. Epub, 2010 Aug 9. PMID:20696765 doi:10.1074/jbc.M110.120451
- ↑ Ridley AJ, Paterson HF, Johnston CL, Diekmann D, Hall A. The small GTP-binding protein rac regulates growth factor-induced membrane ruffling. Cell. 1992 Aug 7;70(3):401-10. PMID:1643658
- ↑ Vincent S, Settleman J. The PRK2 kinase is a potential effector target of both Rho and Rac GTPases and regulates actin cytoskeletal organization. Mol Cell Biol. 1997 Apr;17(4):2247-56. PMID:9121475
- ↑ Bristow JM, Sellers MH, Majumdar D, Anderson B, Hu L, Webb DJ. The Rho-family GEF Asef2 activates Rac to modulate adhesion and actin dynamics and thereby regulate cell migration. J Cell Sci. 2009 Dec 15;122(Pt 24):4535-46. doi: 10.1242/jcs.053728. Epub 2009, Nov 24. PMID:19934221 doi:10.1242/jcs.053728
- ↑ Hamill KJ, Hopkinson SB, DeBiase P, Jones JC. BPAG1e maintains keratinocyte polarity through beta4 integrin-mediated modulation of Rac1 and cofilin activities. Mol Biol Cell. 2009 Jun;20(12):2954-62. doi: 10.1091/mbc.E09-01-0051. Epub 2009, Apr 29. PMID:19403692 doi:10.1091/mbc.E09-01-0051
- ↑ Li X, Lee AY. Semaphorin 5A and plexin-B3 inhibit human glioma cell motility through RhoGDIalpha-mediated inactivation of Rac1 GTPase. J Biol Chem. 2010 Oct 15;285(42):32436-45. doi: 10.1074/jbc.M110.120451. Epub, 2010 Aug 9. PMID:20696765 doi:10.1074/jbc.M110.120451
- ↑ Giordano S, Corso S, Conrotto P, Artigiani S, Gilestro G, Barberis D, Tamagnone L, Comoglio PM. The semaphorin 4D receptor controls invasive growth by coupling with Met. Nat Cell Biol. 2002 Sep;4(9):720-4. PMID:12198496 doi:10.1038/ncb843
- ↑ Aurandt J, Vikis HG, Gutkind JS, Ahn N, Guan KL. The semaphorin receptor plexin-B1 signals through a direct interaction with the Rho-specific nucleotide exchange factor, LARG. Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12085-90. Epub 2002 Aug 26. PMID:12196628 doi:10.1073/pnas.142433199
- ↑ Swiercz JM, Kuner R, Offermanns S. Plexin-B1/RhoGEF-mediated RhoA activation involves the receptor tyrosine kinase ErbB-2. J Cell Biol. 2004 Jun 21;165(6):869-80. PMID:15210733 doi:10.1083/jcb.200312094
- ↑ Tong Y, Hota PK, Penachioni JY, Hamaneh MB, Kim S, Alviani RS, Shen L, He H, Tempel W, Tamagnone L, Park HW, Buck M. Structure and function of the intracellular region of the plexin-b1 transmembrane receptor. J Biol Chem. 2009 Dec 18;284(51):35962-72. Epub . PMID:19843518 doi:10.1074/jbc.M109.056275
- ↑ Janssen BJ, Robinson RA, Perez-Branguli F, Bell CH, Mitchell KJ, Siebold C, Jones EY. Structural basis of semaphorin-plexin signalling. Nature. 2010 Sep 26. PMID:20877282 doi:10.1038/nature09468
- ↑ Bell CH, Aricescu AR, Jones EY, Siebold C. A Dual Binding Mode for RhoGTPases in Plexin Signalling. PLoS Biol. 2011 Aug;9(8):e1001134. Epub 2011 Aug 30. PMID:21912513 doi:10.1371/journal.pbio.1001134
- ↑ Bell CH, Aricescu AR, Jones EY, Siebold C. A Dual Binding Mode for RhoGTPases in Plexin Signalling. PLoS Biol. 2011 Aug;9(8):e1001134. Epub 2011 Aug 30. PMID:21912513 doi:10.1371/journal.pbio.1001134
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