High impact information on CSK

• Cloning and sequencing of chicken C-terminal Src kinase (CSK), a tyrosine kinase that phosphorylates the regulatory C-terminal tyrosine residue present on cytoplasmic tyrosine kinases of the Src family, demonstrated a high degree of interspecies conservation as well as src homology 2 and 3 domains N-terminal to the kinase domain [1].
• Since complex formation between c-Src and CSK seemed a likely regulatory step in the control of c-Src kinase activity, such an association was investigated by immunoprecipitation and Western blotting as well as intracellular localization studies [1].
• On the basis of indirect evidence, we previously suggested that this is caused by partial dephosphorylation at Tyr-527, the phosphorylation of which suppresses c-Src kinase activity [2].
• Unlike the highly homologous cellular c-Src kinase, a C-terminal deletion of the regulatory tail and numerous point mutations make the viral kinase uncontrollable [3].
• Notably, the deficiency of CSK, a negative regulator of Src-family PTK, promoted ionomycin-induced apoptosis of DT-40 cells [4].

Biological context of CSK

• The chicken proto-oncoprotein c-Src is phosphorylated by p34cdc2 during mitosis concomitant with increased c-Src tyrosine kinase activity [2].

Associations of CSK with chemical compounds

• The lack of autophosphorylation sites distinguishes CSK from other tyrosine kinases [1].
• Alternatively, mRNA and protein levels of c-src kinase (CSK), which inactivates pp60c-src by phosphorylating Y527, are not altered by the steroid [5].

References