This gene encodes a protein belonging to the Rho guanine exchange factor (GEF) family of proteins, which activate GTPases by replacing GDP with GTP. This family member is a RhoA GEF that plays a role in endothelial cell migration and tube formation. It is required for angiogenesis and may function in neuronal cell differentiation. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Oct 2013]