Catalytic activity:ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. ,Disease:Defects in JAK3 are a cause of severe combined immunodeficiency autosomal recessive T-cell-negative/B-cell-positive/NK-cell-negative (T (-) B (+) NK (-) SCID) [MIM:600802]. SCID refers to a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity , leukopenia , and low or absent antibody levels. Patients with SCID present in infancy with recurrent , persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development. ,Domain:Possesses two phosphotransferase domains. The second one probably contains the catalytic domain (By similarity) , while the presence of slight differences suggest a different role for domain 1. ,Function:Tyrosine kinase of the non-receptor type , involved in the interleukin-2 and interleukin-4 signaling pathway. Phosphorylates STAT6 , IRS1 , IRS2 and PI3K. ,online information:JAK3 mutation db ,PTM:Tyrosine phosphorylated in response to IL-2 and IL-4. ,similarity:Belongs to the protein kinase superfamily. Tyr protein kinase family. JAK subfamily. ,similarity:Contains 1 FERM domain. ,similarity:Contains 1 protein kinase domain. ,similarity:Contains 1 SH2 domain. ,subcellular location:Wholly intracellular , possibly membrane associated. ,subunit:Interacts with STAM2 and MYO18A (By similarity) . Interacts with SHB. ,tissue specificity:In NK cells and an NK-like cell line but not in resting T-cells or in other tissues. The S-form is more commonly seen in hematopoietic lines , whereas the B- and M-forms are detected in cells both of hematopoietic and epithelial origins. ,
展开内容