Showing posts with label protein. Show all posts
Showing posts with label protein. Show all posts

Sunday, September 8, 2013

How G protein help in signal transmission in to the cell from an incoming ligand & outline the steps.


  • Ligand bind G protein coupled receptor which has α ,β & γ subunits.
  • After binding, GTP in α dissociates from β & γ( all 3 subunits can produce physiological effects)
  • Causes production of a 2nd messenger eg:-cAMP via activation of adenylyl cyclase.
  • cAMP produce activated protein kinase A( pKA)  à  pKA phosphorylate certain molecules & activate /inhibit  à brings about the physiological action
  • When work is done , intrinsic GTPase activity of GTP-α converts GTP to GDP   à α ,β & γ subunits reassociates  à action terminates.
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