Cellular communication 7 Flashcards
Platelet aggregation is induced by ADP binding to
P2YRs
ALL neuropeptides act on ____________ receptors and most often induce alterations in the _______________
metabotropic receptors; alteration in the excitability of postsynaptic cells
Nitric oxide acts as a ___________________________ signaling molecule
autocrine and paracrine
Generation of NO requires
NADPH
molecular oxygen
& is catalyzed by a family of oxygenases known as NO synthases
What are the three families of nitric oxide synthase?
NOS1 also called cNOS or nNOS
NOS2 of iNOS
NOS3 also known as eNOS
NOS1 & NOS3 are __________-dependent enzymes
calcium
NO effects depend on its
tissue concentration
At low concentrations, NO functions as a
signaling molecule and interacts with a cytoplasmic receptor
At higher concentrations, NO exhibits
signaling effects by modifying proteins by nonenzymatic S-nitrosylation
At even higher concentrations, _____________ effects of NO dominate
cytotoxic effects
NO facilitates
sleep
contributes to normal feeding behavior
has a role in GI function
____________________ is an activity-dependent increase in synaptic efficacy
Long-term potentiation
_________________ is a decrease in synaptic efficacy due to prolonged “weak” stimulation of a synapse
Long-term depression
Are GTP and ATP classified as purines or pyrimidines?
purines
What enzyme converts ATP to adenosine in the synaptic cleft?
ectonucleotidase
Are all neuropeptide receptors ionotropic or metabotropic?
metabotropic
What signaling complex activates nNOS?
Ca2+/CaM (calmodulin)
What cytosolic heme-containing enzyme is activated by NO?
soluble guanylyl cyclase (sCG)
The receptor for insulin is a:
a. receptor guanylyl cyclase
b. receptor tyrosine kinase
c. tyrosine kinase-associated receptor
d. receptor serine/threonine kinase
b. receptor tyrosine kinase
What are the five major categories of enzyme-linked receptors?
receptor guanylyl cyclases
receptor tyrosine kinases
tyrosine kinase-associated receptors
receptor serine/threonine kinases
receptor tyrosine phosphatases
Receptor ________________- converts GTP to cGMP.
guanylyl cyclases
______________ are the largest family of enzyme-linked receptors
receptor tyrosine kinases
These are ligands to receptor tyrosine kinases:
insulin & growth factors
Mutations in receptor tyrosine kinases are associated with
a wide variety of cancers
Tyrosine kinase-associated receptors do not have
intrinsic enzyme activity
_______________________ are important mediators of cell growth and differentiation.
receptor serine/threonine kinases
The following are ligands for receptor guanylyl cyclase:
ANP
BNP
CNP (C-type natriuretic peptide)
___________________, a recombinant version of native natriuretic peptides, is used in the treatment of decompensated heart failure
Nesiritide
The ligands for receptor tyrosine kinases are
hormones such as insulin and various growth factors
The insulin receptor is present on most tissues, but the energy-storing tissues ________, _________, and ________ express higher levels of the receptor and have greater responses to insulin.
liver, muscle, & adipocytes
Ligands with tyrosine kinase-associated receptors are
cytokines, including many interleukins, interferons, erythropoietin, growth hormone, prolactin, and leptin
This receptor is associated with the JAK-STAT downstream receptor
tyrosine kinase-associated receptors
This receptor is responsible for cell-differentiation
serine-threonine kinase receptors
TGF-B is a ligand with this receptor
serine-threonine kinase receptors
This is a leptin receptor
tyrosine kinase-associated receptors
Which signaling molecules bind to nuclear receptors? (select 3)
a. acetylcholine
b. testosterone
c. vitamin D
d. erythropoietin
e. triiodothyronine
f. gamma-aminobutyric acid
b. testosterone
c. vitamin D
e. triiodothyronine
Ligated (ligand-bound) nuclear receptor complexes are activated transcription factors that regulate the
expression of target genes in the DNA
The intracellular receptor family includes receptors for
steroid hormones, prostaglandins, vitamin D, thyroid hormones, and retinoic acid
____________ increase basal metabolic rate by stimulating futile cycles of catabolism and anabolism
thyroid hormones
___________________ are activated transcription factors that bind in a highly specific manner to short DNA sequences called hormone response elements
Ligand-bound nuclear receptors
The nuclear receptor family is classically divided into two subfamilies:
receptors for steroid hormones
receptors for retinoic acid, thyroid hormone, and vitamin D.
Steroid hormone receptors are
homodimers
Receptors for retinoic acid, thyroid hormones, and vitamin D form
heterodimers
Which specific thyroid hormone occupies the most thyroid receptors in the euthyroid state?
T3 (triiodothyronine)
The DNA-binding site for ligand-bound nuclear receptors is called a/n:
hormone response element
An unoccupied cytoplasmic intracellular receptor is frequently complexed to a/n:
chaperone protein (heat shock protein)
What syndrome is associated with congenital hypothyroidism?
cretinism
