Janus kinase 3 (tyrosine-protein kinase JAK3, JAK-3, leukocyte janus kinase, L-JAK) (JAK3)
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Function
- tyrosine kinase of the non-receptor type
- role in IL-2 & iIL-4 signaling pathway
- phosphorylates STAT6, IRS1, IRS2 & PI3K
- interacts with STAM2 & MYO18A (putative)
- interacts with SHB
- Tyr phosphorylated in response to IL-2 & IL-4
Structure
- 2 phosphotransferase domains
- domain 2 probably contains the catalytic domain
- domain 1 probably has a different role
- belongs to the Tyr protein kinase family, JAK subfamily
- contains 1 FERM domain
- contains 1 protein kinase domain
- contains 1 SH2 domain
Compartment
- intracytoplasmic membrane, peripheral membrane (putative)
- wholly intracellular, possibly membrane associated
Alternative splicing
- named isoforms=3
- at least one of isoforms may be inactive as it lacks some part of the kinase domain
Expression
- expressed in NK cells & an NK-like cell line but not in resting T-cells or in other tissues
- S-form is more commonly seen in hematopoietic lines, whereas the B- & M-forms are detected in cells both of hematopoietic & epithelial origins
Pathology
- defects in JAK3 are a cause of autosomal recessive T-cell negative/B-cell positive type of severe combined immunodeficiency
More general terms
References
- ↑ UniProt http://www.uniprot.org/uniprot/P52333.html
- ↑ GeneReviews https://www.genecards.org/cgi-bin/carddisp.pl?gene=JAK3
- ↑ Ihle JN et al Signaling by the cytokine receptor superfamily: JAKs and STATs TIBS 19:222 1994 PMID: https://www.ncbi.nlm.nih.gov/pubmed/8048164
- ↑ Kawamura M, McVicar DW, Johnston JA, Blake TB, Chen YQ, Lal BK, Lloyd AR, Kelvin DJ, Staples JE, Ortaldo JR, et al. Molecular cloning of L-JAK, a Janus family protein-tyrosine kinase expressed in natural killer cells and activated leukocytes. Proc Natl Acad Sci U S A. 1994 Jul 5;91(14):6374-8. PMID: https://www.ncbi.nlm.nih.gov/pubmed/8022790