Suppression Of Tumorigenicity 5 (ST5)

ST5 was identified by its ability to suppress the tumorigenicity of Hela cells in nude mice. The protein encoded by this gene contains a C-terminal region that shares similarity with the Rab 3 family of small GTP binding proteins. This protein preferentially binds to the SH3 domain of c-Abl kinase, and acts as a regulator of MAPK1/ERK2 kinase, which may contribute to its ability to reduce the tumorigenic phenotype in cells. Three alternatively spliced transcript variants of this gene encoding distinct isoforms are identified.ST5 gene encodes 3 isoforms with all 3 isoforms containing a C-terminal DENN domain but only isoforms 1 and 3 containing an ABL1-interacting domain. Quantitative PCR analysis detected a relatively uniform ST5 expression pattern in human fetal tissue.