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Unformatted text preview: Review 10.25.07 p12#3, #4 p15#4 p14#4 p16#6 Review Session 10/26/06 1, 2,3 P12#3 Both adrenaline and light receptors are composed of a 7-transmembrane receptor in association with a trimeric Gprotien (eg they are both G-protein coupled receptors). However the ligand for adrenaline is a diffusable hormone but the ligand for photoreceptors -retinal -is covalently bonded to the receptor. For both pathways the Galpha-GPT subunit disengages and activates an effector, but for adrenaline the transducer is G alpha s and the effector is adenylyl clyclase, while for light the transducer is Galpha t and the effector is phosphodiesterase. The end result of receptor activation is therefore different, because the adenylyl cyclase makes cAMP, while the phosphodiesterase breaks down cGMP Charateristics in common Different G protein coupled receptors Ligand is diffusible hormone vs covalently bound Galpha-GTP is effector Adenylyl cyclase vs phosphodiesterase Affects cyclic nucleotide availability Cyclic nucleotide affected is cAMP vs cGMP Draw both complete pathways (again) P12#4 How cAMP regulation illustrates a. signaling through protein kinase cascade (glycogen breakdown) Adrenaline acting on adrenaline receptors results in an increase in cAMP. CAMP activates PKA which activates phosphorylase kinase, which activates glycogen phosphorylase, which transfers a Pi to Glycogen to release a p-glucose molecule....
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This note was uploaded on 05/18/2008 for the course BIO 328 taught by Professor Cabot during the Fall '07 term at SUNY Stony Brook.
- Fall '07