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Allosteric Regulation by Protein Phosphorylation

Major mechanism by which cells response to extracelluar stimuli
1. e.g. hormones, light, neutrophic factors, cytokines
2. Virtually every kind of neuronal protein is regulated by phosphorylation
Protein Kinase transfers phosphate groups from ATP to side chains of serine, threonine or tyrosine on the substrate protein.
1. How is the activity of the substrate protein terminated?
  1. By protein phosphatase = dephosphorylates by hydrolysis
2. Protein Kinases may also activate or modify other protein kinases downstream, or transcription factors such as ERK
3. There are 2 kinds of Protein Kinases
  1. 99% phosphorylate serine or threonine residues
    1. e.g. cAMP-dependant PKA which when activated translocates to nucleus to phosphorylate CREB on residue ser133.
  2. 1% phosphorylate tyrosine kinases (PTK)
    1. e.g. growth-factor receptors where ligand binding induces dimerisation and the Tyr residues are transphosphorylated

Allosteric Regulation by Protein Phosphorylation

	Created by Sophie Barrett almost 11 years ago