BMS 360 Lecture Notes - Signal Transduction, Phospholipase C, Cyclic Adenosine Monophosphate
Document Summary
Peptide hormones (h) cannot enter their target cells and must combine with membrane receptors (r) that initiate signal transduction processes. Signal (peptide hormone) receptor intracellular signaling molecules target protein response. Intracellular signaling molecules are amplifier enzymes or second messengers. Binding conformation change subunit gtp is activated enzyme activated (e. g. adenylylcyclase, which turns atp camp) camp is 2nd messenger. Adenylylcyclase is amplifier enzyme activated, then processes many molecules (not just one) camp second messenger (figure 5-9) Ip3 and dag second messenger (fig 5-10) Phospholipase c activated pip2 acted on ip3 (travels to er, ca2+) and dag (activates pkc [protein kinase c]) phosphorylates proteins call response. Ligand (egf) binding and receptor aggregation autophosphorylation of tyrosines binding of cytosolic proteins with sh2 domains activated plc stimulates insp3-dag pathway activated grb2-sos stimulated ras pathway. Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. Steroid hormone receptors are typically in the cytoplasm or nucleus.
