May facilitate the release of atrial natriuretic peptide by cardiomyocytes and hence play a role in the regulation of arterial pressure. GTP + H2O = GDP + H(+) + phosphate Interacts with CADPS. Expressed in heart and brain. In the brain, expression restricted to neurons of the cortex, hippocampus and cerebellum. Sparse expression in the brainstem and almost absent in the hypothalamic region. In the heart, expressed in cardiomyocytes. Not detected in interstitial tissue or vascular cells. At 9.5 dpc, detected in the developing heart, skeletal myotomes and dorsal portion of the neural tube. At 13.5 and 15.5 dpc, expressed in the heart and neural tissue including the central and peripheral nervous system. In the embryonic brain, expression is restricted to more mature neurons and absent from the progenitor neuronal cells of the ventricular zone. Also present in mature peripheral neurons, such as the neurons of the dorsal root ganglia and the Auerbach's and Meissner's plexi of the intestinal tract. No obvious phenotype. Mutant mice are viable and fertile. Belongs to the small GTPase superfamily. Ras family.