RAP1 GTPase Activating Protein (RAP1GAP)

Specific GTPase-activating proteins that play regulatory roles in this enzymatic process have been identified for RAS homologous protein (ARHG) and RAP1A. The best defined of these is RAS-GTPase activating protein (RASA), overexpression of which can suppress the transforming activity of RAS.

The p21 protein RAP1 is of particular interest since it has been shown to be an antagonist of RAS and is capable of suppressing cellular transformation. It has been suggested that RAP1 binds competitively to RASA, thus interfering with its RAS effector functions.It was shown to be highly expressed in undifferentiated tumor cells, suggesting that it may have a role in differentiation and growth of malignant cells.