BIOL 2021 Lecture Notes - Lecture 12: Visual Phototransduction, Diglyceride, Photon
Document Summary
Ch 15 cell signalling camp effects: fast-seconds (ex. Glycogen muscle: slow response- gene expression transcription. A) destroy camp camp amp phosphodiesterase: phosphatase dephosphorylate targets of pka. Substrate= phosphatidyl inositol 4,5-bisphosphate pi(4,5)p2 = pip2. This substrate is less than 1% of pm lipids. Dag- 2 roles: fatty acids cleaved off arachidonic acid eicosanoids include prostaglandin. Aspirin inhibits prostaglandin synthesis: dag + ca2+ + ptdser. The protein kinases are special ca2+/calmodulin- dependent kinases (cam-kinases) Photoreceptor= gpcr = rhodopsin (not the same as bacteria rhodopsin which is a h+ pump) Has an isomerization (11 cis all trans). Dark high cgmp= channels open (in the dark) = cells depolarized. High depolarization= high rate of neurotransmitter release. Light destroy cgmp (ion channels close) = cell hyperpolarizes. Gpcr kinase=grk: dock protein on gpcr. Can activate some (same pathway as gpcr) Different: cytosolic domain has enzymatic activity or associates with enzymes. Or ligands are proteins on another cell.
