Rap2B: Proteins and Enzymes

The Ras-related proteins Rap1A and Rap1B share 95 percent identity, while Rap2A and Rap2B share 91 percent identity. Together, they constitute a grouping within the Ras superfamily of small GTPases. Like other GTPases, Rap proteins transduce signals by cycling between an active GTP-bound and an inactive GDP-bound state. Rap1 and Rap2A counteract the mitogenic function of Ras, and are implicated in the regulation of integrins. Rap2B is a platelet protein that is activated by thrombin and involved in platelet activation.