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Rnd2/Rho7 GTPases Rnd2/Rho7 is a member of the novel Rho subfamily Rnd, together with Rnd1/Rho6 and Rnd3/RhoE/Rho8. Rnd2/Rho7 is transiently expressed in radially migrating cells in the brain while they are within the subventricular zone of the hippocampus and cerebral cortex. These migrating cells typically develop into pyramidal neurons. Cells that exogenously expressed Rnd2/Rho7 failed to migrate to upper layers of the brain, suggesting that Rnd2/Rho7 plays a role in the radial migration and morphological changes of developing pyramidal neurons, and that Rnd2/Rho7 degradation is necessary for proper cellular migration. The Rnd2/Rho7 GEF Rapostlin is found primarily in the brain and together with Rnd2/Rho7 induces dendrite branching. Unlike Rnd1/Rho6 and Rnd3/RhoE/Rho8, which are RhoA antagonists, Rnd2/Rho7 binds the GEF Pragmin and significantly stimulates RhoA activity and Rho-A mediated cell contraction. Rnd2/Rho7 is also found to be expressed in spermatocytes and early spermatids, with male-germ-cell Rac GTPase-activating protein (MgcRacGAP), where it localizes to the Golgi-derived pro-acrosomal vesicle. Most Rho proteins contain a lipid modification site at the C-terminus, with a typical sequence motif CaaX, where a = an aliphatic amino acid and X = any amino acid. Lipid binding is essential for membrane attachment, a key feature of most Rho proteins.
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