RAP1GAP: Proteins and Enzymes

Rap1GAP, an 85/95kDa protein, is a member of a family of GAP's specific for Rap1 (1). Though to be an important tumor suppressor, Rap1GAP has no sequence homology with other GAPs such as RasGAP, RanGAP and RhoGAP. Purified as a cytosolic and membrane-bound protein, both isoforms consist of two monomers each contain a dimerization and a catalytic domain (2-4). Mutations in the GAP domain of the tumor suppressor tuberin, can cause benign tumor phenotype tuberous sclerosis (5).