PTPs are cell signaling molecules that play regulatory roles in a variety of cellular processes. PTP 4A family contains a protein tyrosine phosphatase (PTPase) domain and a characteristic C-terminal prenylation motif. PTP4A2 has been shown to primarily associate with plasmic and endosomal membrane through its C-terminal prenylation. PTP4A2 was found to interact with the beta-subunit of Rab geranylgeranyltransferase II (beta GGT II), and thus may function as a regulator of GGT II activity. Overexpression of this gene in mammalian cells conferred a transformed phenotype, which suggested its role in tumorigenesis. Alternatively spliced transcript variants that encode two distinct isoforms have been described.