ID:JAK3_HUMAN DESCRIPTION: RecName: Full=Tyrosine-protein kinase JAK3; EC=2.7.10.2; AltName: Full=Janus kinase 3; Short=JAK-3; AltName: Full=Leukocyte janus kinase; Short=L-JAK; FUNCTION: Non-receptor tyrosine kinase involved in various processes such as cell growth, development, or differentiation. Mediates essential signaling events in both innate and adaptive immunity and plays a crucial role in hematopoiesis during T-cells development. In the cytoplasm, plays a pivotal role in signal transduction via its association with type I receptors sharing the common subunit gamma such as IL2R, IL4R, IL7R, IL9R, IL15R and IL21R. Following ligand binding to cell surface receptors, phosphorylates specific tyrosine residues on the cytoplasmic tails of the receptor, creating docking sites for STATs proteins. Subsequently, phosphorylates the STATs proteins once they are recruited to the receptor. Phosphorylated STATs then form homodimer or heterodimers and translocate to the nucleus to activate gene transcription. For example, upon IL2R activation by IL2, JAK1 and JAK3 molecules bind to IL2R beta (IL2RB) and gamma chain (IL2RG) subunits inducing the tyrosine phosphorylation of both receptor subunits on their cytoplasmic domain. Then, STAT5A AND STAT5B are recruited, phosphorylated and activated by JAK1 and JAK3. Once activated, dimerized STAT5 translocates to the nucleus and promotes the transcription of specific target genes in a cytokine-specific fashion. CATALYTIC ACTIVITY: ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. SUBUNIT: Interacts with STAM2 and MYO18A (By similarity). Interacts with SHB. INTERACTION: Q07666:KHDRBS1; NbExp=2; IntAct=EBI-518246, EBI-1364; SUBCELLULAR LOCATION: Endomembrane system; Peripheral membrane protein (By similarity). Cytoplasm (By similarity). 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-form is detected in cells both of hematopoietic and epithelial origins. 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. PTM: Tyrosine phosphorylated in response to IL-2 and IL-4. 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]. A form of severe combined immunodeficiency (SCID), 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 present in infancy 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. 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. SEQUENCE CAUTION: Sequence=AAC50227.1; Type=Miscellaneous discrepancy; Note=Wrong choice of CDS. Was erroneously described as an isoform JAK3M while it is a fragmentary mRNA of INSL3; WEB RESOURCE: Name=Atlas of Genetics and Cytogenetics in Oncology and Haematology; URL="http://atlasgeneticsoncology.org/Genes/JAK3ID41032ch19p13.html"; WEB RESOURCE: Name=JAK3base; Note=JAK3 mutation db; URL="http://bioinf.uta.fi/JAK3base/"; WEB RESOURCE: Name=GeneReviews; URL="http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/gene/JAK3"; WEB RESOURCE: Name=SeattleSNPs; URL="http://pga.gs.washington.edu/data/jak3/";
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on P52333
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
