protein tyrosine kinase 6; breast tumor kinase; tyrosine protein kinase BRK (PTK6 BRK)
Jump to navigation
Jump to search
Function
- phosphorylates KHDRBS1, KHDRBS2, KHDRBS3 & STAP2/BKS
- may function as an intracellular signal transducer in epithelial tissues
- overexpression in mammary cells leads to mitogenically sensitization to EGF, & results in a partially transformed phenotype
- presence in the nucleus appears to be linked to suppression of tumor progression
- activated enzyme seems to have greater access to its substrates
- autophosphorylated
- phosphorylation of Tyr-447 may lead to the autoinhibition of the enzyme
- interacts with GAP-A.p65 (putative)
- interacts with KHDRBS1
- interacts with phosphorylated IRS4
- interacts with ADAM15
Structure
- belongs to the protein kinase superfamily, Tyr protein kinase family, BRK/PTK6/SIK subfamily
- contains 1 protein kinase domain
- contains 1 SH2 domain
- contains 1 SH3 domain
Compartment
- cytoplasm, nucleus
- colocalizes with KHDRBS1, KHDRBS2 or KHDRBS3, within the nucleus
- in secretory epithelial cells from prostate adenocarcinoma, nuclear localization is higher in low-grade & lower in high-grade regions of the tumors
Expression
- epithelia-specific
- very high level in colon
- high levels in small intestine & prostate
- low levels in some fetal tissues
- expressed at low level in some breast tumors, but not in normal breast
- also found in melanocytes
- not expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney & pancreas