RAP1A, Member Of RAS Oncogene Family (RAP1A)

RAP1A belongs to the family of RAS-related proteins. The most striking difference between RAP proteins and RAS proteins resides in their 61st amino acid: glutamine in RAS is replaced by threonine in RAP proteins. The product of this gene counteracts the mitogenic function of RAS because it can interact with RAS GAPs and RAF in a competitive manner. Two transcript variants encoding the same protein have been identified for this gene.

RAS1-mediated signaling pathways in Drosophila are not influenced by RAP1 levels, suggesting that RAS1 and RAP1 function via distinct pathways. Moreover, a mutation that abolishes the putative cAMP-dependent kinase phosphorylation site of Drosophila RAP1 can still rescue the RAP1 mutant phenotype.