2yin
From Proteopedia
STRUCTURE OF THE COMPLEX BETWEEN Dock2 AND Rac1.
Structural highlights
Function[DOCK2_HUMAN] Involved in cytoskeletal rearrangements required for lymphocyte migration in response of chemokines. Activates RAC1 and RAC2, but not CDC42, by functioning as a guanine nucleotide exchange factor (GEF), which exchanges bound GDP for free GTP. May also participate in IL2 transcriptional activation via the activation of RAC2.[1] [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.[2] [3] [4] [5] [6] 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.[7] [8] [9] [10] [11] Publication Abstract from PubMedDOCK (dedicator of cytokinesis) guanine nucleotide exchange factors (GEFs) activate the Rho-family GTPases Rac and Cdc42 to control cell migration, morphogenesis, and phagocytosis. The DOCK A and B subfamilies activate Rac, whereas the DOCK D subfamily activates Cdc42. Nucleotide exchange is catalyzed by a conserved DHR2 domain (DOCK(DHR2)). Although the molecular basis for DOCK(DHR2)-mediated GTPase activation has been elucidated through structures of a DOCK9(DHR2)-Cdc42 complex, the factors determining recognition of specific GTPases are unknown. To understand the molecular basis for DOCK-GTPase specificity, we have determined the crystal structure of DOCK2(DHR2) in complex with Rac1. DOCK2(DHR2) and DOCK9(DHR2) exhibit similar tertiary structures and homodimer interfaces and share a conserved GTPase-activating mechanism. Multiple structural differences between DOCK2(DHR2) and DOCK9(DHR2) account for their selectivity toward Rac1 and Cdc42. Key determinants of selectivity of Cdc42 and Rac for their cognate DOCK(DHR2) are a Phe or Trp residue within beta3 (residue 56) and the ability of DOCK proteins to exploit differences in the GEF-induced conformational changes of switch 1 dependent on a divergent residue at position 27. DOCK proteins, therefore, differ from DH-PH GEFs that select their cognate GTPases through recognition of structural differences within the beta2/beta3 strands. Multiple Factors Confer Specific Cdc42 and Rac Protein Activation by Dedicator of Cytokinesis (DOCK) Nucleotide Exchange Factors.,Kulkarni K, Yang J, Zhang Z, Barford D J Biol Chem. 2011 Jul 15;286(28):25341-51. Epub 2011 May 24. PMID:21613211[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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