Chapter 15 Signal transduction.ppt

Chapter 15: Signal transduction Know the terminology: Enzyme-linked receptor, G-protein linked receptor, nuclear hormone receptor, G-protein, adaptor protein, scaffolding protein, SH2 domain, MAPK, Ras, protein kinase, MAPK, protein phosphatase, phospholipase, phosphodiesterase, cAMP, crosstalk, Chapter 15: Signal transduction Outline: General principles of signal transduction Overview of: Signaling Receptors Transducers Targets Major types of cell-surface receptors RTK signaling G-protein signaling General Principles of Signal Transduction 1. Communication usually involves a (i) signaling molecule, (ii) a receptor, (iii) intracellular signal transducers and (iv) targets General Principles of Signal Transduction General Principles of Signal Transduction 3. Different cells respond differently to a particular signaling molecule General Principles of Signal Transduction 4. Cells can remember the effects of some signals 5. Cells can adjust their sensitivity to a signal General Principles of Signal Transduction 4. Cells can remember the effects of some signals 5. Cells can adjust their sensitivity to a signal General Principles of Signal Transduction 6. Signal can exhibit complex responses to signal concentration Signaling molecules Signaling molecules come in many chemical forms: Proteins: insulin, glucagon Steroids et al.: testosterone, estradiol, cortisol Amines: thyroxine, catecholamines, acetylcholine Gases: nitric oxide Signaling pathways require molecules with rapid rates of synthesis and degradation Typically released from one cell and recognized by another cell Signaling molecules Secretory signals: Autocrine-signals affect same cell or cell type Paracrine-signals affect neighbouring cell Endocrine-signals affect distant cells Contact-dependent signals: -signals are not released but affect other cells in contact through protein-protein interactions Autocrine signaling Signals released by one cell affect other cells in the immediate vicinity Amp