BIOLOGY 2B03 Lecture Notes - Lecture 6: Apoptosis, Ptpn6, Stat5
5 Dec 2017
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Document Summary
Epo receptor (epor: epor is a cytokine receptor that is linked to the jak-stat signal transduction pathway, cellular response in the target cell include inhibition of cell death, changes in pattern of gene expression and differentiation. Receptor dimerization and autophosphorylation: epor- has 3 fractional domains: the cytosolic domain, the transmembrane domain, and the extracellular domain, each epor is associated with a jak kinase on its cytosolic domain. Jak kinase, unphosphorylated state= inactive with very weak kinase activity: dimerization of the receptor by epo brings the 2 jak kinases close together, so close that weak kinase activity is sufficient to phosphorylate a neighbouring jak kinase. It is called autophosphorylation: phosphorylation of the activation lip on jak kinases activates kinase activity. Jak kinases have many targets of phosphorylation, including tyrosine residues on the intracellular domain of the receptor: the jak kinase is specifically tyrosine kinase, meaning that only tyrosine residue is phosphorylated.
