Chapter 16 Flashcards
G-protein coupled receptor (GPCR) definition
cell-surface receptor that associates with an intracellular trimeric GTP-binding protein (G-protein) after activation by an extracellular ligand
embedded in the membrane by seven transmembrane alpha helices
G-protein definition
membrane-bound GTP-binding protein involved in intracellular signaling
composed of three subunits
usually activated by the binding of a hormone or other ligand to a transmembrane receptor
some G proteins directly regulate the activity of _____
ion channels
adenylyl cyclase definition
enzyme that catalyzes the formation of cyclic AMP from ATP
important component in some intracellular signaling pathways
cyclic AMP definition
small intracellular signaling molecule generated from ATP in response to hormonal stimulation of cell-surface receptors
enzyme-coupled receptor definition
transmembrane protein that, when stimulated by the binding of a ligand, activates an intracellular enzyme
receptor tyrosine kinase (RTK) definition
enzyme-coupled receptor in which the intracellular domain has a tyrosine kinase activity, which is activated by ligand binding to the receptor’s extracellular domain
Ras definition
one of the small GTP-binding proteins that helps relay signals from cell-surface receptors to the nucleus
monomeric GTPase definition
small, single-subunit GTP-binding protein
part of many different signaling pathways
MAP-kinase signaling module definition
set of three functionally interlinked protein kinases that allows cells to respond to extracellular signal molecules that stimulate proliferation
MAP kinase definition
mitogen-activated protein kinase
signaling molecule that is the final kinase in a three-kinase sequence called the MAP-kinase signaling module
phosphoinositide 3-kinase (PI 3-kinase) definition
enzyme that phosphorylates inositol phospholipids in the plasma membrane, generating docking sites for intracellular signaling proteins that promote cell growth and survival
nuclear receptor definition
protein inside a eukaryotic cell that, on binding to a signal molecule, enters the nucleus and regulates transcription
receptor serine/threonine kinase definition
enzyme-coupled receptor that phosphorylates target proteins on serine or threonine
What cell signaling do plant cells seem to not use?
RTKs, steroid-hormone-type nuclear receptors, cyclic AMP
