Dock180 is part of a large class of proteins (GEFs) which contribute to cellular signalling events by activating small G proteins. In their resting state G proteins are bound to Guanosine diphosphate (GDP) and their activation requires the dissociation of GDP and binding of guanosine triphosphate (GTP). GEFs activate G proteins by promoting this nucleotide exchange.
Dock180 and related proteins differ from other GEFs in that they do not possess the canonical structure of tandem DH-PH domains known to elicit nucleotide exchange. Instead they possess a DHR2 domain which mediates Rac activation by stabilising it in its nucleotide-free state.[5] Dock180-related proteins also possess a DHR1 domain which has been shown, in vitro, to bind phospholipids[6] and which may be involved in their interaction with cellular membranes. Other structural features of Dock180 include an N-terminalSH3 domain involved in binding to ELMO proteins (see below)[7] and a C-terminalproline-rich region which, in Myoblast city (the Drosophila melanogaster ortholog of Dock180), was shown to bind DCrk (the Drosophila ortholog of Crk).[8]
Regulation of Dock180 Activity
Under physiological conditions Dock180 alone is inefficient at promoting nucleotide exchange on Rac.[7] Effective GEF activity requires an interaction between Dock180 and its binding partner ELMO. ELMO1 is the most comprehensively described isoform of this small family of non-catalytically active proteins which function to recruit Dock180 to the plasma membrane and induce conformational changes which increase GEF efficiency.[9][10][11] ELMO1 has also been reported to inhibit ubiqitinylation of Dock180 and so prevent its degradation by proteasomes.[12]Receptor-mediated activation of RhoG (a small G protein of the Rac subfamily) is perhaps the best known inducer of Dock180 GEF activity. Active (GTP-bound) RhoG recruits the ELMO/Dock180 complex to the plasma membrane thereby bringing Dock180 into contact with its substrate, Rac.[13] In tumour cells Dock180 is regulated by a complex containing Crk and p130Cas which is in turn regulated by cooperative signalling by β3-containing integrin complexes and the membrane-bound protein uPAR.[14]
↑Meller N, Merlot S, Guda C (November 2005). "CZH proteins: a new family of Rho-GEFs". J. Cell Sci. 118 (Pt 21): 4937–46. doi:10.1242/jcs.02671. PMID16254241.
↑ 5.05.1Côté JF, Vuori K (December 2002). "Identification of an evolutionarily conserved superfamily of DOCK180-related proteins with guanine nucleotide exchange activity". J. Cell Sci. 115 (Pt 24): 4901–13. doi:10.1242/jcs.00219. PMID12432077.
↑Lu M, Kinchen JM, Rossman KL, et al. (2004). "PH domain of ELMO functions in trans to regulate Rac activation via Dock180". Nature Structural & Molecular Biology. 11 (8): 756–62. doi:10.1038/nsmb800. PMID15247908.
↑Lu M, Kinchen JM, Rossman KL, et al. (February 2005). "A Steric-inhibition model for regulation of nucleotide exchange via the Dock180 family of GEFs". Curr. Biol. 15 (4): 371–77. doi:10.1016/j.cub.2005.01.050. PMID15723800.
↑Makino Y, Tsuda M, Ichihara S, et al. (March 2006). "Elmo1 inhibits ubiquitylation of Dock180". J. Cell Sci. 119 (Pt 5): 923–32. doi:10.1242/jcs.02797. PMID16495483.
↑Katoh H, Negishi M (July 2003). "RhoG activates Rac1 by direct interaction with the Dock180-binding protein Elmo". Nature. 424 (6947): 461–64. doi:10.1038/nature01817. PMID12879077.
↑Gumienny TL, Brugnera E, Tosello-Trampont AC, et al. (October 2001). "CED-12/ELMO, a novel member of the CrkII/Dock180/Rac pathway, is required for phagocytosis and cell migration". Cell. 107 (1): 27–41. doi:10.1016/S0092-8674(01)00520-7. PMID11595183.
↑Moore CA, Parkin CA, Bidet Y, et al. (September 2007). "A role for the Myoblast city homologues Dock1 and Dock5 and the adaptor proteins Crk and Crk-like in zebrafish myoblast fusion". Development. 134 (17): 3145–53. doi:10.1242/dev.001214. PMID17670792.
↑Nishihara H, Kobayashi S, Hashimoto Y, Ohba F, Mochizuki N, Kurata T, Nagashima K, Matsuda M (Nov 1999). "Non-adherent cell-specific expression of DOCK2, a member of the human CDM-family proteins". Biochim. Biophys. Acta. 1452 (2): 179–87. doi:10.1016/s0167-4889(99)00133-0. PMID10559471.
↑Gu J, Sumida Y, Sanzen N, Sekiguchi K (Jul 2001). "Laminin-10/11 and fibronectin differentially regulate integrin-dependent Rho and Rac activation via p130(Cas)-CrkII-DOCK180 pathway". J. Biol. Chem. 276 (29): 27090–7. doi:10.1074/jbc.M102284200. PMID11369773.
↑Matsuda M, Ota S, Tanimura R, Nakamura H, Matuoka K, Takenawa T, Nagashima K, Kurata T (Jun 1996). "Interaction between the amino-terminal SH3 domain of CRK and its natural target proteins". J. Biol. Chem. 271 (24): 14468–72. doi:10.1074/jbc.271.24.14468. PMID8662907.
↑Gumienny TL, Brugnera E, Tosello-Trampont AC, Kinchen JM, Haney LB, Nishiwaki K, Walk SF, Nemergut ME, Macara IG, Francis R, Schedl T, Qin Y, Van Aelst L, Hengartner MO, Ravichandran KS (Oct 2001). "CED-12/ELMO, a novel member of the CrkII/Dock180/Rac pathway, is required for phagocytosis and cell migration". Cell. 107 (1): 27–41. doi:10.1016/s0092-8674(01)00520-7. PMID11595183.
↑Brugnera E, Haney L, Grimsley C, Lu M, Walk SF, Tosello-Trampont AC, Macara IG, Madhani H, Fink GR, Ravichandran KS (Aug 2002). "Unconventional Rac-GEF activity is mediated through the Dock180-ELMO complex". Nat. Cell Biol. 4 (8): 574–82. doi:10.1038/ncb824. PMID12134158.
Further reading
Takai S, Hasegawa H, Kiyokawa E, et al. (1996). "Chromosomal mapping of the gene encoding DOCK180, a major Crk-binding protein, to 10q26.13-q26.3 by fluorescence in situ hybridization". Genomics. 35 (2): 403–4. doi:10.1006/geno.1996.0378. PMID8661160.
deBakker CD, Haney LB, Kinchen JM, et al. (2004). "Phagocytosis of apoptotic cells is regulated by a UNC-73/TRIO-MIG-2/RhoG signaling module and armadillo repeats of CED-12/ELMO". Curr. Biol. 14 (24): 2208–16. doi:10.1016/j.cub.2004.12.029. PMID15620647.
Yin J, Haney L, Walk S, et al. (2004). "Nuclear localization of the DOCK180/ELMO complex". Arch. Biochem. Biophys. 429 (1): 23–29. doi:10.1016/j.abb.2004.05.014. PMID15288806.
Matsuda M, Ota S, Tanimura R, et al. (1996). "Interaction between the amino-terminal SH3 domain of CRK and its natural target proteins". J. Biol. Chem. 271 (24): 14468–72. doi:10.1074/jbc.271.24.14468. PMID8662907.
Wu YC, Horvitz HR (1998). "C. elegans phagocytosis and cell-migration protein CED-5 is similar to human DOCK180". Nature. 392 (6675): 501–4. doi:10.1038/33163. PMID9548255.
Albert ML, Kim JI, Birge RB (2001). "alphavbeta5 integrin recruits the CrkII-Dock180-rac1 complex for phagocytosis of apoptotic cells". Nat. Cell Biol. 2 (12): 899–905. doi:10.1038/35046549. PMID11146654.
Tu Y, Kucik DF, Wu C (2001). "Identification and kinetic analysis of the interaction between Nck-2 and DOCK180". FEBS Lett. 491 (3): 193–9. doi:10.1016/S0014-5793(01)02195-0. PMID11240126.
Gu J, Sumida Y, Sanzen N, Sekiguchi K (2001). "Laminin-10/11 and fibronectin differentially regulate integrin-dependent Rho and Rac activation via p130(Cas)-CrkII-DOCK180 pathway". J. Biol. Chem. 276 (29): 27090–7. doi:10.1074/jbc.M102284200. PMID11369773.
Zhou Z, Caron E, Hartwieg E, et al. (2001). "The C. elegans PH domain protein CED-12 regulates cytoskeletal reorganization via a Rho/Rac GTPase signaling pathway". Dev. Cell. 1 (4): 477–89. doi:10.1016/S1534-5807(01)00058-2. PMID11703939.
Grimsley CM, Kinchen JM, Tosello-Trampont AC, et al. (2004). "Dock180 and ELMO1 proteins cooperate to promote evolutionarily conserved Rac-dependent cell migration". J. Biol. Chem. 279 (7): 6087–97. doi:10.1074/jbc.M307087200. PMID14638695.
Wang X, Wu YC, Fadok VA, et al. (2003). "Cell corpse engulfment mediated by C. elegans phosphatidylserine receptor through CED-5 and CED-12". Science. 302 (5650): 1563–6. doi:10.1126/science.1087641. PMID14645848.