BIO315H5 Lecture Notes - Lecture 3: Platelet-Activating Factor, Calcium Signaling, Cytoskeleton
Document Summary
Lecture 3: mechanisms of g protein-coupled receptor (gpcr) signaling (chapter 15, pp. Gpcrs: g-protein coupled receptors; represent the largest family of cell surface receptors. There are ~800 known human genes that encode gpcrs (or ~4% of the protein-coding genome). One ligand can bind to multiple gpcrs and one gpcr can bind to more than one ligand. All gpcrs have 7 transmembrane (tm) domains that traverse the plasma membrane, an extracellular n-terminus, and an intracellular c-terminus, and an intracellular loop between tm-v and vi that binds to heterotrimeric g proteins. Gpcr signals through activation of heterotrimeric g proteins. The gpcr superfamily includes rhodopsin, the light-activated protein in the vertebrate eye, as well as the large number of olfactory receptors in the vertebrate nose. Green is the receptor and the red is a ligand. When the ligand binds to the receptor, it causes small conformation changes which is a very important aspect of gpcr signaling.
