Protein Domain : IPR020693

Type:  Family Name:  Tyrosine-protein kinase, non-receptor Jak2
Description:  Janus kinases (JAKs) are tyrosine kinases that function in membrane-proximal signalling events initiated by a variety of extracellular factors binding to cell surface receptors []. Many type I and II cytokine receptors lack a protein tyrosine kinase domain and rely on JAKs to initiate the cytoplasmic signal transduction cascade. Ligand binding induces oligomerisation of the receptors, which then activates the cytoplasmic receptor-associated JAKs. These subsequently phosphorylate tyrosine residues along the receptor chains with which they are associated. The phosphotyrosine residues are a target for a variety of SH2 domain-containing transducer proteins. Amongst these are the signal transducers and activators of transcription (STAT) proteins, which, after binding to the receptor chains, are phosphorylated by the JAK proteins. Phosphorylation enables the STAT proteins to dimerise and translocate into the nucleus, where they alter the expression of cytokine-regulated genes. This system is known as the JAK-STAT pathway.Four mammalian JAK family members have been identified: JAK1, JAK2, JAK3, and TYK2. They are relatively large kinases of approximately 1150 amino acids, with molecular weights of ~120-130kDa. Their amino acid sequences are characterised by the presence of 7 highly conserved domains, termed JAK homology (JH) domains. The C-terminal domain (JH1) is responsible for the tyrosine kinase function. The next domain in the sequence (JH2) is known as the tyrosine kinase-like domain, as its sequence shows high similarity to functional kinases but does not possess any catalytic activity. Although the function of this domain is not well established, there is some evidence for a regulatory role on the JH1 domain, thus modulating catalytic activity. The N-terminal portion of the JAKs (spanning JH7 to JH3) is important for receptor association and non-catalytic activity.This entry represents the non-receptor tyrosine kinase JAK2 []. JAK2 was initially cloned using a PCR-based strategy utilising primers corresponding to conserved motifs within the catalytic domain of protein-tyrosine kinases []. In common with JAK1 and TYK2, and by contrast with JAK3, JAK2 appears to be ubiquitously expressed. Short Name:  Tyr_kinase_non-rcpt_Jak2

0 Child Features

9 Contains

DB identifier Type Name
IPR000719 Domain Protein kinase domain
IPR011009 Domain Protein kinase-like domain
IPR020635 Domain Tyrosine-protein kinase, catalytic domain
IPR001245 Domain Serine-threonine/tyrosine-protein kinase catalytic domain
IPR000980 Domain SH2 domain
IPR000299 Domain FERM domain
IPR019749 Domain Band 4.1 domain
IPR017441 Binding_site Protein kinase, ATP binding site
IPR008266 Active_site Tyrosine-protein kinase, active site

1 Cross References


0 Found In

6 GO Annotations

GO Term Gene Name Organism
GO:0004715 IPR020693
GO:0005524 IPR020693
GO:0042393 IPR020693
GO:0006468 IPR020693
GO:0035556 IPR020693
GO:0016020 IPR020693

1 Parent Features

DB identifier Type Name
IPR016251 Family Tyrosine-protein kinase, non-receptor Jak/Tyk2

0 Proteins

2 Publications

First Author Title Year Journal Volume Pages PubMed ID