Advanced Cell Chapter 15

Signal Transduction

process by which cell-surface receptors convert extracellular signals into intracellular ones; most extracellular signal molecules bind to specific receptor proteins on the surface of the target cells and do not enter the cytosol or nucleus

Ion-Channel-Coupled Receptors

also known as transmitter-gated ion channels or ionotrophic receptors; involved in rapid synaptic signaling between nerve cells and other excitable target cells

Enzyme-Coupled Receptors

function directly as enzymes or associate directly with enzymes that they activate, usually a single-pass transmembrane protein that have their ligand-binding site outside the cell and its catalytic or enzyme-binding site inside; heterogenous in structure; mainly protein kinases or associate with protein kinase

G Protein-Coupled receptors

indirectly regulate the activity of a separate plasma-membrane bound target protein, which is generally either an enzyme or an ion channel; mediate most responses to external world as well as signals from other cells

Trimeric GTP-Binding Protein

mediates interaction between the activated receptors and a target protein; the activation of the target protein can change the concentration of small intracellular mediators or ion permeability

Cyclic AMP

synthesized from ATP by PM-bound adenylyl cyclase through a cyclization reaction that removes two phosphate groups; rapidly and continuously destroyed by cyclic AMP phosphodiesterases

Receptor Tyrosine Kinases

class of enzyme-coupled receptor; directly phosphorylate specific tyorsine’s on themselves and on a small set of intracellular signaling proteins; ~60 human encoding genes that can be classified into ~20 structural subfamilies with their own family of complimentary ligands