FUNCTION: SwissProt: P63000 # 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.
SIZE: 192 amino acids; 21450 Da
SUBUNIT: Interacts with the GEF proteins PREX1, RASGRF2, DOCK1, DOCK2 and DOCK7, which promote the exchange between GDP and GTP, and therefore activate it. Interacts with PARD6A, PARD6B and PARD6G in a GTP-dependent manner. Part of a quaternary complex containing PARD3, some PARD6 protein (PARD6A, PARD6B or PARD6G) and some atypical PKC protein (PRKCI or PRKCZ), which plays a central role in epithelial cell polarization. Found in a trimeric complex composed of DOCK1 and ELMO1, which plays a central role in phagocytosis of apoptotic cells. Interacts with RALBP1 via its effector domain. Interacts with PLXNB1. Part of a complex with MAP2K3, MAP3K3, CCM2 and DEF6. Interacts with BAIAP2, CYFIP1/SRA-1 and DEF6. Interacts with Y.pseudotuberculosis YPKA and PLCB2.
SUBCELLULAR LOCATION: Cell membrane; Lipid-anchor; Cytoplasmic side (By similarity). Melanosome. Note=Inner surface of plasma membrane possibly with attachment requiring prenylation of the C- terminal cysteine (By similarity). Identified by mass spectrometry in melanosome fractions from stage I to stage IV.
TISSUE SPECIFICITY: Isoform B is predominantly identified in skin and epithelial tissues from the intestinal tract. The expression of isoform B is elevated in colorectal tumors at various stages of neoplastic progression, as compared to their respective adjacent tissues.
DOMAIN: SwissProt: P63000 The effector region mediates interaction with DEF6.
SIMILARITY: Belongs to the small GTPase superfamily. Rho family.