Rho GDP-dissociation inhibitor 1 （ARHGDIA） is a member of the RAS gene superfamily， which encodes small guanine nucleotide exchange （GTP/GDP） factors. ARHGDIA， which is localized to the cytoplasm， inhibits the dissociation of GDP from Rho proteins， thus preventing GTP from binding to and consequently activating Rho proteins. In humans， the ARHGDIA can be phosphorylated at Ser 101 by p21-activated kinase， an event that inhibits its activity and may result in positive feedback regulation of several ARHGDIA target proteins.
