BIO315H5 Lecture Notes - Lecture 4: Transducin, Isomerization, Arrestin
Document Summary
Camkii as a frequency decoder of ca2+ oscillations: camkii can be converted to long lasting gene transcription because it can phosphorylate. Creb and cause changes in gene expression: can decode ca2+ signal, need 4 subunits to make an hollow enzyme. In this case, the beta-gamma acts on k+ channels and activate them, leading to hyperpolarization, making the cell less excitable. This phosporylation prevent rhodopsin to activate transducin: phosphorylated site recruits arrestin and can inhibit the activity of gpcr by. The receptor can be endocytosed and taken away from the site where it downregulation can be activated: gaps such as rgss, affecting guanylyl cyclase activity itself. Close ca2+ channels, drop in ca2+, this drop stimulates further production of cgmp by gc: all these mechanisms represent negative feedback, signal transduction is flexible and sensitive. Once a receptor gets activated, you can inactivate it. Ex. of grk, rhodopsin kinase, can phosphorylate : receptor sequestration.
