BIO 392 Lecture Notes - Lecture 4: G Protein–Coupled Receptor, Nicotinic Acetylcholine Receptor, Cell Physiology
Document Summary
Broad range of receptor types: ion channels and g-protein coupled receptors, intrinsic kinase activity. Activate intracellular signaling cascades that affect cell function: growth, transcription, translation, migration, secretion. Complex signal transduction cascades help with signal integration, regulation, signal amplification and overcome special limitations. Signal amplification is the activation of one receptor that can induce several molecules and amplify a signal. Ligand binding opens/closes channel changes receptor conformation and channel opens through membrane potential increase net diffusion of ions across plasma membrane allows specific ions to pass. Nach receptor aids in muscle function, when acetyl choline binds the channel opens. Some receptors (insulin) have intrinsic activity, mostly rtks. Ligand binding changes the conformation of a receptor and activates enzyme autophosphorylation of receptor first messenger. Phosphotyrosines on cytoplasmic domain of receptor serve as docking sites for proteins. Bound docking proteins bind/activate other proteins which activate signaling pathways all involve activation of cytoplasmic proteins via phosphorylation.
