Biology 2382B Lecture Notes - Lecture 15: Protein Kinase A, Muscarinic Acetylcholine Receptor, Cgmp-Dependent Protein Kinase
16 Aug 2017
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Gpcrs fast acting effectors: k+ channels. Gpcrs that regulate adenylyl cyclase: camp, epithelial cell cl- channels, pka, creb. Gpcrs that activate phospholipase c: ca2+, ip3, dag, pkc, no, cgmp, pkg. Chapter 15: p. 693-694, 699-705, 709-711, 714-716. Activation of muscarinic acetylcholine receptor and k+ channels in the heart. Acetylcholine (ach) neurotransmitter involved in muscular contraction. Active muscarinic acetylcholine receptor (gpcr) has an extracellular domain to bind acetylcholine. When acetylcholine binds its receptor, it recruits trimeric g protein complex, displacing. Binding of gtp to g triggers dissociation of g from both the receptor and from g(cid:533)(cid:534). G(cid:533)(cid:534) subunit move along on lipid anchor on plasma membrane, binds to and activates the effector protein (k+ channel): usually g activates effector; this is one of the rare exceptions. K+ channel opens and causes cellular hyperpolarization: this happens in cardiac muscle cells. Cellular hyperpolarization results in a slower rate of heart muscle contraction.
