Rho Guanine Nucleotide Exchange Factor 11 (ARHGEF11)

Gtrap48 shares 90% amino acid identity with human KIAA0380, as well as significant homology with ARHGEF1. Gtrap48 possesses a PDZ domain, an RGS sequence, tandem DH and PH domains characteristic of guanine nucleotide exchange factors for the Rho family of G proteins, and 2 proline-rich sequences. Northern blot analysis detected a 7.5-kb Gtrap48 mRNA in brain tissue. Longer exposure revealed a low level of expression in liver and kidney. Gtrap48 was expressed predominantly in rat cerebellum, with low level immunoreactivity in striatum, hippocampus, and thalamus.Gtrap48 was found to activate Rho. Expression of Gtrap48 induced reorganization of the actin cytoskeleton. When Gtrap41 and Gtrap48 were coexpressed, Gtrap41 colocalized with actin in structures that resembled actin stress fibers.