Rho/Cdc42 Guanine Nucleotide Exchange Factor 6 (ARHGEF6)

ARHGEF6 belongs to a family of cytoplasmic proteins that activate the Ras-like family of Rho proteins by exchanging bound GDP for GTP. It may form a complex with G proteins and stimulate Rho-dependent signals. This protein is activated by PI3-kinase. Mutations in this gene can cause X-chromosomal non-specific mental retardation.

Sequence analysis predicted that the 776-amino acid PIXA protein contains an N-terminal SH3 domain, a Dbl-homology (DH) domain, and a pleckstrin homology (PH) domain, suggestive of a Rho GEF. Northern blot analysis detected an approximately 5.0-kb transcript in heart, muscle, thymus, spleen, and placenta, with lower expression in brain, prostate, and testis, and little or no expression in lung, liver, and kidney.