BIOL 3755 Chapter Notes - Chapter 5: Adrenergic Receptor, Cell Membrane, Signal Transduction
Document Summary
Types of receptors: plasma membrane receptors, plasma membrane receptors are transmembrane proteins span entire membrane thickness, has hydrophobic segments extending out from membrane into ec fluid and hydrophilic segments extending into ic fluid. Intracellular receptors: not located in membranes but exist in either cytosol or cell nucleus and have very different structure, have segment that binds messenger and other segments that act as regulatory. Regulation of receptors: downregulation ~ decrease in total number of target cell receptors for given messenger, may occur in response to chronic high ec concentration of messenger. Internalization : upregulation ~ increase in total number of target cell receptors for given messenger, may occur in response to chronic low ec concentration of messenger. 5. 2 signal transduction pathways: receptor activation ~ change in receptor conformation caused by combination of messenger with receptor, signal transduction pathways ~ sequences of mechanisms that relay info from plasma membrane receptor to cell"s response mechanism.
