Receptor-Mediated Signal Transduction ystems CELL-SURFACE RECEPTORS plasma membrane cell-surface recepto Receptors Cell Surface Receptors; hydrophilic signal molecule Nuclear receptors INTRACELLULAR RECEPTORS small hydrophobic signal molecule carrier protein intracellular receptor
Receptors: ⚫ Cell Surface Receptors; ⚫ Nuclear Receptors Receptor-Mediated Signal Transduction Systems
Cell-surface receptors 1. Process of transmembrane signal transduction a Synthesis and secretion of signaling molecules a Receptor binding and initiation of intracellular signaling pathway a Regulation of cellular metabolism, function, gene expression, etc a Down-regulation or termination of cellular responses EXTRACELLULAR SIGNAL MOLECULE RECEPTOR PROTEIN CYTOPLASM FLUID REception 2 Transduction 3 Respo Recepto INTRACELLULAR SIGNALING PROTEINS Signal-transduction pathway molecule Plasma membrane 83 TARGET PROTEINS altered altered cel movement
1. Process of transmembrane signal transduction Cell-surface receptors Synthesis and secretion of signaling molecules Receptor binding and initiation of intracellular signaling pathway Regulation of cellular metabolism, function, gene expression, etc Down-regulation or termination of cellular responses
2. Classification of cell-surface receptors Ion-channel-linked receptors Involved in rapid synaptic signaling between electrically excitable cells G-protein coupled receptors(GPCR Seven-pass transmembrane protein, indirectly regulate the activity of a target protein through a trimeric GTP-binding protein(G-protein) Enzyme-linked receptors Single-pass transmembrane protein function directly as enzyme or directly associated with enzymes they activate Others
2. Classification of cell-surface receptors • Ion-channel-linked receptors – Involved in rapid synaptic signaling between electrically excitable cells • G-protein coupled receptors (GPCR) – Seven-pass transmembrane protein, – indirectly regulate the activity of a target protein through a trimeric GTP-binding protein (G-protein) • Enzyme-linked receptors – Single-pass transmembrane protein, – function directly as enzyme or directly associated with enzymes they activate • Others
A ION-CHANNEL-LINKED RECEPTORS Figure 15-15 Three classes of cell-surface receptors. (A) lon-channel linked receptors. (B)G-protein-linked plasma membrane receptors, and(c)enzyme-linked signal molecule receptors. Although many enzyme-linked receptors have intrinsic enzyme activity, as shown on the left, many others rely on associated enzymes, as shown on the 8 G-PROTEIN-LINKED RECEPTORS signal molecule G protein activated activated G protein enzyme O ENZYME-LINKED RECEPTORS ignal molecule signal molecule nform of a dime inactive catalytic active catalytic activated domain enzyme
Ion Channel linked receptor (Ligand-gated Ion Channel 1. Classification ClassI nAchR, Gabar, 5-HT3R GlyR Class l glutamate/ Aspartate Receptor Class Il CGMP/CAMPR, IP3R, ryanodine r Class Iv aTP/aDP gated channel(P2x) 2. Structure. w ons g 突触侧 胞浆侧
Ion Channel Linked Receptor (Ligand-gated Ion Channel) 1. Classification: Class I nAchR, GABAR, 5-HT3R, GlyR Class II Glutamate/Aspartate Receptor Class III cGMP/cAMPR, IP3R, ryanodine R Class IV ATP/ADP gated channel (P2X) 2. Structure: