RASA3 stimulates the GTPase activity of Ras p21, and in doing so functions as a negative regulator of the Ras signalling pathway. UniProt describes it as an inhibitory regulator of the Ras-cyclic AMP pathway. The protein binds inositol tetrakisphosphate (IP4) with high affinity, and it might be a specific IP4 receptor. Specifically, NCBI Gene describes binding to inositol 1,3,4,5-tetrakisphosphate.

The RASA3 gene encodes Ras GTPase-activating protein 3, which is localised to the cell membrane through a pleckstrin homology (PH) domain in its C-terminal region. Consistent with this, HGNC places the gene in the groups of pleckstrin homology domain containing proteins and C2 and RasGAP domain containing proteins. Alternative splicing of the RASA3 gene results in multiple transcript variants. Mouse and rat each have an orthologous gene, Rasa3.

The protein has also been catalogued under the aliases GAP1IP4BP and GAPIII. Because it links an inositol phosphate-binding function to the control of Ras activity, RASA3 is of interest to researchers studying Ras regulation, membrane-associated signalling and GAP-family proteins. RASA1 is another member of the RAS p21 protein activator family and is a useful comparison when studying Ras GTPase-activating proteins.