Signal-1-临床五年制2014.pptVIP

（3）Mode of action of extracellular molecules (胞外/间信息分子的作用方式） A. Endocrine B. Paracrine C. Autocrine D. Synaptic-dependent E. Contact-dependent F. Gap-junction A. Endocrine B. Paracrine C. Autocrine D. Synaptic-dependent E. Contact-dependent F. Gap-junction Gap junction （连接小体） Extracellular/intercellular molecules (细胞外/间信息分子) （first messenger) 激素作用内分泌，化学介质旁分泌 神经递质在突触，表面接触气体异 Classification of signaling molecules Extracellular/intercellular molecules (细胞外/间信息分子) （Also called first messenger) Intracellular(细胞内) molecules 2. Intracellular molecules Signal transducers (信号转导分子) ◆Second messengers (第二信使) ◆ Proteins ◆ Third messengers (第三信使) (1) Second messenger: ◆ Definition: Small molecules, synthesized in cells in response to an external signal, are responsible for intracellular signal transduction. ◆Classification of second messengers A. Ions: Ca2+ B. Lipid derivatives : DG/DAG (diglyceride /diacylglycerol, 二脂酰甘油), Cer(ceramide, 神经酰胺）, IP3(inositol triphosphate, 三磷 酸肌醇) C. Nucleotides: cAMP，cGMP （2）Proteins: ◆ Located inside of the cells ◆ including enzymes, regulating proteins(regulators), transcriptional factors(TFs), etc. ◆ They are switchers and adaptors in the signaling pathways. Examples: Enzymes: Protein kinase/Protein phosphatase Regulators: G proteins TFs: NF-kB (3) Third messengers: ◆ Third messengers are the molecules which transmit message from outside to inside of nucleous or from inside to outside of nucleous, also called DNA binding proteins. ◆ Half life is short ◆ Usually encoded by immediate-early genes Effect by membrane receptors Effect by intracellular receptors Intracellular molecules Extracellular molecules Signal molecules Second messengers: cAMP，IP3, Ca2+ P