Study Set Content:
MAJOR RECEPTORS
Ligand-gated ion channels
G protein-coupled receptors
Enzymes-linked receptors
Intracellular receptors
changes in membrane
potential or ionic concentration with cell
Ligand-gated ion channels
protein phosphorylation
G protein-coupled receptors
protein phosphorylation and
altered gene expression.
Intracellular receptors
protein and receptors
phosphorylation
Enzymes-linked receptors
Several biologic ligands are sufficiently lipid-soluble to cross the
plasma membrane and act on
intracellular receptors.
One class of such ligands includes
steroids
steroids
(corticosteroids,
mineralocorticoids, sex, steroids, vitamin D),
One class of such ligands includes steroids (corticosteroids,
mineralocorticoids, sex, steroids, vitamin D), and
thyroid hormone
The glucocorticoid receptor polypeptide is schematically depicted as
a protein with
three distinct domains.
binds to the receptors in the
absence of hormone and prevents folding into the active
conformation of the receptors.
A heat-shock protein, hsp90,
The binding of a (blank)causes dissociation of the hsp90 stabilizer and
permits conversion to the active configuration.
hormone ligand
(steroid)
is a highly abundant molecular chaperone that plays an
essential role in man cellular processes including cell cycle control,
cell survival, hormone, and other signaling pathways.
Hsp90
TWO MAIN FUNCTIONS OF RECEPTORS
1. Ligand binding
2. Activation of an effector system (message propagation)
is a substance (usually a small molecule) that forms a
complex with bio-molecules to serve a biological purpose.
ligand
transduce drug-receptor interactions into cellular effects.
Effectors
LIGAND-REGULATED TRANSMEMBRANE ENZYMES
INCLUDING RECEPTOR
TYROSINE KINASES
This class of receptor molecules mediates the first steps in
signaling by
by insulin, epidermal growth factor (EGF), platelet-derived
growth factors (PDGR), atrial natriuretic peptide (ANP),
transforming growth factor-β (TGR-β), and many other trophic
hormones.
These receptors are polypeptides consisting of an
an extracellular
hormone-binding domain and a cytoplasmic enzymes domain,
These receptors are polypeptides consisting of an extracellular
hormone-binding domain and a cytoplasmic enzymes domain, which
may be a
a protein tyrosine kinase, a serine kinase, or a guanylyl
cyclase.
