該基因編碼的蛋白參與多種途徑，包括src家族激酶的調控。它通過與蛋白酪氨酸磷酸酶（ptpn22）基因編碼的蛋白結合，在t細胞活化中發揮重要作用。該蛋白也在多種底物上磷酸化C末端酪氨酸殘基，包括SRC原癌基因、非受體酪氨酸激酶基因編碼的蛋白質磷酸化抑制src家族酪氨酸激酶的激酶活性。該基因的內含子多態性（rs34933034）已被發現影響b細胞的活化，并與系統性紅斑狼瘡（sle）有關。選擇性剪接導致多個轉錄變體[由RefSeq提供，2017年8月]
The protein encoded by this gene is involved in multiple pathways, including the regulation of Src family kinases. It plays an important role in T-cell activation through its association with the protein encoded by the protein tyrosine phosphatase, non-receptor type 22 (PTPN22) gene. This protein also phosphorylates C-terminal tyrosine residues on multiple substrates, including the protein encoded by the SRC proto-oncogene, non-receptor tyrosine kinase gene. Phosphorylation suppresses the kinase activity of the Src family tyrosine kinases. An intronic polymorphism (rs34933034) in this gene has been found to affect B-cell activation and is associated with systemic lupus erythematosus (SLE). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2017]