BIOL 300 Lecture Notes - Phosphodiesterase, Gtpase, Conformational Change
15 Dec 2012
School
Department
Course
Professor
Document Summary
G-protein coupled receptors (gpcrs) are seven-pass tm receptors; these receptors can be hormones, neurotransmitters, light (rhodopsin), odorants and act largely physiologically: while most receptors are dimer, all. Gpcrs are monomers: on the extracellular side is the ligand- binding domain and on the intracellular part is the domain which will interact with a g-protein. In the resting state, when the hormone is not yet secreted, gpcrs are not ligand-bound and the signal transduction pathway is off . In this resting state, the g=protein is in a trimeric form where the alpha subunit is gdp bound. When the ligand is bound, the gpcr can bind to the g-alpha which kicks out the gdp and activates the g-alpha subunits: therefore, for this procedure, the. At this point, g-alpha will leave the g- protein because of a conformational change caused by binding of gtp, and will travel through the membrane to its target (the effector)
