JAK3
JAK3 (Janus kinase 3, also known as L-JAK or JAKL) is a non-receptor tyrosine kinase that relays cytokine receptor signals in immune cells. It phosphorylates receptor tails and STAT proteins, linking ligand binding to gene transcription. Browse Assay Genie's current range of JAK3 research reagents below, or read on for the biology behind the target.
JAK3 is a non-receptor tyrosine kinase involved in cell growth, development and differentiation. It mediates essential signalling events in both innate and adaptive immunity and plays a crucial role in haematopoiesis during T-cell development. In the cytoplasm it acts through its association with type I cytokine receptors that share the common gamma subunit, including IL2R, IL4R, IL7R, IL9R, IL15R and IL21R.
After ligand binding, JAK3 phosphorylates specific tyrosine residues on the cytoplasmic tails of the receptor, creating docking sites for STAT proteins. It then phosphorylates the recruited STATs, which form homodimers or heterodimers and translocate to the nucleus to activate gene transcription. In IL-2 signalling, JAK1 and JAK3 bind the IL2RB and IL2RG subunits and phosphorylate both. STAT5A and STAT5B are then recruited and activated, and dimerised STAT5 promotes transcription of target genes in a cytokine-specific manner.
The JAK3 gene encodes a member of the Janus kinase family, which belongs to the Tyr protein kinase family within the protein kinase superfamily. The protein is predominantly expressed in immune cells and is activated by tyrosine phosphorylation downstream of interleukin receptors. Mutations in the JAK3 gene are associated with autosomal severe combined immunodeficiency disease (SCID). Mouse and rat orthologs, both named Jak3, are annotated.
JAK3 has a crucial role in haematopoiesis during T-cell development and mediates signalling in both innate and adaptive immunity.
JAK3 associates with common gamma chain receptors such as IL2R, IL4R, IL7R, IL9R, IL15R and IL21R to transduce cytokine signals.
JAK3 phosphorylates receptor tails and STAT proteins, making it a key node for studying STAT5 activation and cytokine-specific transcription.
Mutations in the JAK3 gene are associated with autosomal severe combined immunodeficiency disease, linking the kinase to immune disorders.
JAK3 is a non-receptor tyrosine kinase that transduces cytokine signals. After ligand binding to common gamma chain receptors, it phosphorylates receptor tails and then the recruited STAT proteins, which move to the nucleus and activate gene transcription.
JAK3 is the HGNC symbol for Janus kinase 3. Other names include L-JAK, JAKL, LJAK and JAK-3, and UniProt lists the protein as tyrosine-protein kinase JAK3. It belongs to the Jak family of tyrosine kinases.
Mutations in the JAK3 gene are associated with autosomal severe combined immunodeficiency disease (SCID). Orthologs named Jak3 exist in mouse and rat; check the datasheet of any product for its validated reactivity.
Other Janus kinase family members that act alongside JAK3 in cytokine receptor signalling.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P52333; product specifications from Assay Genie datasheets.