?
RhoGAP_Bcr: RhoGAP (GTPase-activator protein [GAP] for Rho-like small GTPases) domain of Bcr (breakpoint cluster region protein)-like proteins. Bcr is a multidomain protein with a variety of enzymatic functions. It contains a RhoGAP and a Rho GEF domain, a Ser/Thr kinase domain, an N-terminal oligomerization domain, and a C-terminal PDZ binding domain, in addition to PH and C2 domains. Bcr is a negative regulator of: i) RacGTPase, via the Rho GAP domain, ii) the Ras-Raf-MEK-ERK pathway, via phosphorylation of the Ras binding protein AF-6, and iii) the Wnt signaling pathway through binding beta-catenin. Bcr can form a complex with beta-catenin and Tcf1. The Wnt signaling pathway is involved in cell proliferation, differentiation, and cell renewal. Bcr was discovered as a fusion partner of Abl. The Bcr-Abl fusion is characteristic for a large majority of chronic myelogenous leukemias (CML). Small GTPases cluster into distinct families, and all act as molecular switches, active in their GTP-bound form but inactive when GDP-bound. The Rho family of GTPases activates effectors involved in a wide variety of developmental processes, including regulation of cytoskeleton formation, cell proliferation and the JNK signaling pathway. GTPases generally have a low intrinsic GTPase hydrolytic activity but there are family-specific groups of GAPs that enhance the rate of GTP hydrolysis by several orders of magnitude.