G-Protein Coupled Receptors (GPCR) sense extracellular signals and activate different Guanine nucleotide binding proteins (G-proteins) that have alpha, beta and gamma subunits. Upon activation, the alpha subunit of G-proteins dissociates from beta-gamma and the both are then free to regulate downstream effectors. Serine/threonine-protein kinase PAK 1 binds with Rho guanine nucleotide exchange factor 6 (ARHGEF6, PIX-Alpha) in the cytosol and is subsequently translocated by the G-protein beta-gamma complex to the plasma membrane. Here, the GTPase Cell division control protein 42 homolog (CDC42) binds with this complex. Subsequently, ARHGEF6 acts as a GEF for CDC42 and facilitates the activation of CDC42. CDC42 is known to be involved in epithelial cell polarization processes.
guanyl-nucleotide exchange factor activity of G-protein beta-gamma complex:PAK1:ARHGEF6:CDC42 [plasma membrane]