第二节细胞的跨膜信号转导 chap 5 Membrane receptors, second messengers, and signal-transduction pathways from Berne Levy principles of Physiology (4thed)2005
• chap. 5 Membrane receptors, second messengers, and signal-transduction pathways 第二节 细胞的跨膜信号转导 from Berne & Levy Principles of Physiology (4th ed) 2005
regulatory molecules Some regulatory substances enter the cell and bind to receptors Agonists exert their effects on cells via signal- transduction pathway, whereby the binding of an agonist to its plasma membrane receptor elicits an intracellular response by altering the activities of particular cellular proteins
• Some regulatory substances enter the cell and bind to receptors ➢ regulatory molecules • Agonists exert their effects on cells via signaltransduction pathway , whereby the binding of an agonist to its plasma membrane receptor elicits an intracellular response by altering the activities of particular cellular proteins
G protein-coupled receptor receptor ligand-gated ion channel enzyme-lInked receptor
G protein-coupled receptor ligand-gated ion channel enzyme-linked receptor receptor
Ligand Receptor Receptor-ligand Inactive Active G protein G protein Adenylyl cyclase Inactive effector Active enzyme CGMP phosphodiesterase enzyme or ion channel or ion channel H Phospholipase C Phospholipase A2 Ca++or K+ channels Low concentration High concentration ----_ cGMP of second messenger of second messenger PKA Inactive enzyme Active PKG or ion channel Calmodulin-dep kinase ctor enzyme ion channel PKC Ca++ channel K+ channel
G protein-mediated regulatory pathway 1. agonist hormone (via endocrine) local mediator (via paracrine and autocrine) neurotransmitter (via neurosecretion
一. G protein-mediated regulatory pathway 1. agonist • neurotransmitter (via neurosecretion) • local mediator (via paracrine and autocrine) • hormone (via endocrine)