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LEHNINGER PRINCIPLES OF BIOCHEMISTRY
Sixth Edition
David L. Nelson and Michael M. Cox
© 2013 W. H. Freeman and Company
CHAPTER 12Biosignaling
Five features of signal transducing systems
Six general types of signal transducers
The β-adrenergic receptor is a G protein-coupled receptor
Adenylyl cyclase produces cyclic AMP (cAMP) from ATPcAMP is a potent second messenger in epinephrine signaling
The GTPase switch
Regulation of epinephrine
signaling
Activation of cAMP-dependent protein kinase (PKA)
Epinephrine cascade
Desensitization of the β-adrenergic receptor in the
continued presence of epinephrine
Hormone-activated phospholipase C
(PKC) and inositol 1,4,5-triphosphate
(IP3)
Calmodulin often mediates the
effects of calcium
Insulin signalingThe insulin receptor is a
tyrosine kinase
The electrogenic Na+K+ ATPase
produces a transmembrane
electrical potential of about -60 mV
(negative inside the cell)
Free energy change for charged molecule
G = RT ln ( Cin / Cout) + FVm
Z=valence, F=96,500 J/V*mol, Vm=TM electrical potential (volts)
Role of voltage-gated and ligand-gated ion channels in neural
transmission
The acetylcholine receptor ion channel
Steroid hormones
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