Rho Guanine Nucleotide Exchange Factor 4 (ARHGEF4)

Rho-like GTPases are activated by binding GTP and inactivated by conversion of GTP to GDP by their intrinsic GTPase activity. Guanine nucleotide exchange factors (GEFs), such as ARHGEF4, accelerate the GTPase activity of Rho GTPases by catalyzing their release of bound GDP.The full-length ASEF cDNA encodes a protein of 619 amino acids with motifs found in the Dbl (MCF2) family of proteins. ASEF contains Dbl homology (DH), pleckstrin (PLEK) homology (PH), and Src homology-3 (SH3) domains. Northern blot analysis revealed an Asef mRNA of 3.6 kb that was highly expressed in mouse brain. Immunohistochemical analysis revealed high Asef expression in mouse central nervous system, including hippocampus, olfactory bulb, and cerebellum, where Apc is also highly expressed.