BIOM20001 Lecture Notes - Lecture 40: G Protein–Coupled Receptor, Skeletal Muscle, Gtpase
Document Summary
Respond to hormones, neurotransmitters local mediators (e. g. inflammatory mediators like cytokines), light photons, amino acids, fatty acids, purines. Half of all known drugs work on g-protein-linked receptor signaling. Same signal can activate multiple gpcrs (g protein coupled receptor) Depends on cell type e. g. same signal (acetylcholine) causes different responses in different cells. Due to different receptor types(muscarinic is g-protein, nicotinic is an ion channel), different intracellular mediators and different gpcr subtypes. Acetylcholine causes skeletal muscle contraction, heart muscle relaxation, production of saliva. Various types of g-protein which are specific for groups of gpcr. This activation method is similar to the gtpases rab ran and ras. Ligand binds --> conformational change in gpcr--> allows g-protein to bind to gpcr --> gpcr acts as a guanine exchange factor (gef) --> active gpcr causes release of gdp and binding of. Gtp --> gtp causes a conformational change in g-protein and activates alpha subunit and the.
