A small ‘ras-related protein’ (KREV1, 184 aa); a GTP-binding protein that apparently antagonizes ras, has antimitogenic activity, and negatively regulates IL-2 transcription. Mutations in rap1A disrupt cell migration and cause abnormalities in cell shape. Very similar proteins, rap1B (184 aa) and rap2 (183 aa), interact with the cytoskeleton in platelets and neurons and may be involved in NGF-induced neuronal differentiation and T-cell activation. The rap family are activated by CRK adaptor proteins and rap-specific GEFs. See tuberous sclerosis.
Subjects: Medicine and Health.