北大生化chapter12课件.pptVIP

Chapter 12 Biosignaling;Why do we need biosignaling pathways ?;Cellular response;烩鞍棠胺彬孪遮联肄琐嚼奉熬撞钻丫盔蛾掐遵室塑诞壁紧伎浊漾某肚宽勾北大生化chapter12课件北大生化chapter12课件;Requirement of Biosignaling;Criterion 1: specificity;Criterion 2: amplification;Criterion 3: Desensitization;Criterion 4: Integration;Six general types of signal transducers;Type I: gated-ion channels;Role of voltage-gated and ligand-gated ion channels in neural transmission;Three stages of acetylcholine receptor;Type 2: receptor-enzyme units; Physiological role of insulin a. High blood glucose concentration causes increased secretion of insulin and decreased secretion of glucagon; b. Stimulate the glucose transporter, thus the uptake of glucose by muscle and adipose tissue cells; Regulate both fuel metabolism and gene expression: kinase cascade (protein phosphorylation) ? growth response that include increases in synthesis of DNA and mRNA promoting anabolic processes/inhibiting catabolic ones predominantly in muscle, fat and liver tissue; glycogen (in liver and muscle) triacylglycerols (in adipose tissue);Tyr kinase domain of insulin-receptor; IRS: insulin receptor substrate protein kinase : Raf-1, MEK, MAPK (phosphorylate Ser or Tyr residue) MAPK (ERK, extracellular regulated kinase): mitogen - activated protein kinase; MEK (MAPKK): mitogen- activated, ERK-activating kinase ;Multivalent scaffold proteins and membrane rafts;Some binding modules of signaling proteins;Activation of glycogen synthase by insulin;Autoinhibited;Membrane rafts and caveolae may segregate signaling proteins; Diabetes is a defect in insulin production or action a. Diabetes mellitus is caused by a deficiency in the secretion or action of insulin b.Two major clinical classes of the disease: Type I: insulin-dependent diabetes mellitus (IDDM) Type II: non-insulin-dependent diabetes mellitus