Download presentation
Presentation is loading. Please wait.
Published byJohn Walter O’Neal’ Modified over 9 years ago
1
Seven-Transmembrane Receptor Signaling Heterotrimeric G-proteins & Second Messenger Pathways
2
7TM Receptor Interacting with Trimeric G- Protein
3
Canonical 7TM Signaling Pathway - I Activated receptor Binds heterotrimeric G-protein (G ) –specific ones for specific receptors Activated receptor is GEF –exchanges GDP for GTP on G –G dissociates from G G activates/inhibits downstream transducers –adenylyl cyclases –phosphodiesterases –phospholipases G activates/inhibits downstream transducers –inhibition of kinases that inactivate 7TM receptors
4
Canonical 7TM Signaling Pathway – II Adenylyl cyclase –synthesis if cAMP ([cAMP] increase 100X) –cAMP activates protein kinase A (PKA) PKA (S/T kinase) –regulated by RII (regulatory II) subunit RII subunit is binds cAMP or PKA catalytic subunit –deregulation by cAMP allows PKA to phosphorylate numerous substrates –PKA can enter nucleus and phosphorylate many transcriptions factors activates and inhibits
5
Canonical 7TM Signaling Pathway – III Turning off the signals –RGS – regulators of G-protein signaling) GAPs for G subunits that stimulate GTP hydrolysis hydrolysis allows G reassociation –downstream kinases phosphorylate 7TM receptors blocks further G protein stimulation
6
Cyclic Nucleotides
7
Adenylyl Cyclase Converts ATP to cAMP Stimulated by G s Inhibited by G i
8
Removal of Cyclic Nucleotides Phosphodiesterases cut 3'-O-P bond to generate 5' nucleoside monophosphates cAMP AMP cGMP GMP Phosphodiesterase
9
Cyclic Nucleotide Activated Kinases Protein kinases –PKA cAMP cAMP binds to RII subunit releases PKA from autoinhibition –PKG cGMP
10
-Andrenergic Receptors
11
Formation of Lipid 2 nd Messengers
12
Lipid Second Messengers & Targets
13
Lipid 2 nd Messenger Activated Protein Kinases Protein Kinase C Family
14
Phosphoinositol Second Messenger Signaling
15
Ca 2+ Second Messenger Signaling
16
Odorant Receptors
17
Photoreceptors
18
Eicosanoids
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.