The active breakpoint cluster region-related protein (ABR) protein contains multiple domains including a RhoGEF domain, a PH domain, a C1 domain, a C2 domain, and a C-terminal RhoGAP domain. It is related to a slightly larger protein, BCR, which is structurally similar, but has an additional N-terminal kinase domain. ABR has GAP activity for both Rac and Cdc42. It promotes the exchange of RAC or CDC42-bound GDP by GTP, thereby activating them []. This entry represents the PH domain of ABR.
Abr (active breakpoint cluster region-related protein) and Bcr (breakpoint cluster region protein) are homologous proteins containing a C-terminal domain with GTPase-activating protein (GAP) activity specific for Rac. They control multiple cellular functions of murine macrophages []. They contain several domains, including tandem DH-PH, C2 and GAP domains. Bcr has an extra N-terminal oligomerization domain []. Bcr has been shown to fused to Abl tyrosine kinase in leukemia. The fusion of Bcr to Abl deregulates the tyrosine kinase activity of Abl []. The N-terminal oligomerization domain is thought to be the most critical component that allows the formation of homo-tetramer Bcr/Abl complexes and deregulates the Abl tyrosine kinase [, ]. The GTPase-activating activity of Bcr has been shown to be regulated by transglutaminase 2 (TG2), a multifunctional protein that has been implicated in numerous pathologies including that of neurodegeneration and celiac disease [, ].Abr is a critical regulator of Rho and Cdc42 during the single cell wound healing [].
