w6 signal tranduction Flashcards
endocrine
chemical signal by 1 cell type that acts on cells in a DISTANT tissue
paracrine
chemical signal by 1 cell type that acts on a neighboring cell in same tissue (NEAR BY)
autocrine
chemical signal by 1 cell type that acts on the SAME cell that released the signaling molecule
ligand-gated ion channel receptors (ionotropic receptors)
involved in signaling between ELECTRICALLY excitable cells (chemical signal into an electrical signal)
-integral membrane proteins
-hybrid receptor/channels
Acetylcholine, serotonin, and GABA are what type of receptors
ionotropic receptors (ligand-gated ion channel receptors)
G protein-coupled receptors active and inactive when (match w GTP and GDP)
active - GTP
inactive - GDP
how do G protein-coupled receptors work
-works through intermediary separate membrane-associated enzyme or channel
-intermediary is a GTP binding complex (G protein)
what is the largest family of receptors on the cell surface, w more than 1000 members
G protein coupled receptors (GPCRs)
GTP associated w what G protein subunit
alpha
what is the purpose of the beta-gamma subunits in G proteins
anchoring
GDP-GTP exchange stimulates dissociation of the complex how
free alpha subunit + beta-gamma complex
how do u terminate G protein signaling
hydrolyze GTP to GDP
what does RGS do (regulation of G protein signal)
helps stimulate GTP hydrolysis to GDP to help terminate G protein signaling
main purpose of secondary messengers
to amplify signals and integrate responses among cell types
these are examples of what type of messengers
-cAMP
-cGMP
-IP3
-DAG
-arachidonic acid
-CA2+
secondary messengers
Adenylyl cyclase converts what
ATP -> cAMP
Phosphodiesterase
cGMP -> GMP
phospholipases (e.g phospholipase C)
PIP2 -> DAG + IP3
how does adenylyl cyclase work
activates protein kinase A (PKA)
what does protein kinase A do (PKA)
catalyzes transfer of a phosphate group to certain serine or theronin residues
what does phosphodiesterase do
breaks down cyclic nucleotides
(cyclic to non cyclic)
how does phospholipase work
G protein alpha-q subunit activates phospholipase C, which breaks down PIP2 into DAG at IP3
what does DAG activate
stimulates protein kinase C
what does IP3 signal the release of
binds to receptor on the ER membrane and triggers release of Ca2+
stimulation of what resultsin rapid increase in cytosolic IP3 and DAG levels
stimulation of PLCB
what is calmodulin (CaM)
Ca2+ binding protein
each molecule of CaM cooperatively binds how many calcium ions
4
Ca2+-CaM complex activates what commonly
CaM kinases
CaM kinase phosphorylates what residues
serine and threonine
what is an important CaM kinase
myosin light chain kinase (MLCK)
arachidonic acid convert into biologically active metabolites that are collectively called
eicosanoids (all have 20carbon atoms)
arachidonic acid -> eicosanoids pathway
cyclooxygenase produces what
produces thromboxanes, prostaglandins, and prostacyclins
arachidonic acid -> eicosanoids pathway
5-lipoxygenase produces what
leukotrienes, hydroxyeicosatetraenoic acid (HETE)
arachidonic acid -> eicosanoids pathway
epoxygenase produces what
HETE and epoxyeicosatrienoic acid (EET)
what is the primary enzyme responsible for releasing arachidonic acid
phospholipase A2
what catalyzes the conversion of arachidonic acid into the precursors of prostaglandins, prostacyclins, and thromboxanes
cyclooxygenase
how do most NSAIDS (aspirin, acetaminophen, ibuprofen) work
directly target cyclooxygenase
5-lipooxygenase initiates the conversion of arachidonic acid into what
leukotrienes
leukotrienes particiapte in what reponses
allergic, inflammatory
epoxygenase pathways converts arachidonic acid into what 2 products
HETE, EET
what do HETE and EET do
cell proliferation and Ca2+ release
what are the 2 G protein superfamilies
classic heterotrimeric G proteins that bind to G protein-coupled receptors (GPCRs)
small GTP binding proteins such as Ras
activated RTKs transduce their signal using which small GTP binding protein
Ras
receptor guanylyl cyclases
catalyze generation of cGMP from GTP
receptor serine/threonine kinases
phosphorylate serine or threonin residues
receptor tyrosine kinases
phosphorylates tyrosine residues
yrosine kinase associated recptors
interact w cytosolic tyrosine kinases
ceptor tyrosine phosphatases
cleave phosphate groups from tyrosine groups of cellular proteins
atrial natriuretic peptide (ANP) act on what
vascular smooth muscle to dilate blood vessels and enhance Na+ excretion into urine (which is termed natriuresis)
a binding of what induces a conformational change in receptor guanylyl cyclase that causes dimerizatino and activation
natriuretic peptide
what does receptor guanylyl cyclase do
conversion of GTP to cGMP and raises levels of intracellular levels of cGMP
what does increased cGMP cause
RELAXATION of vascular SMOOTH MUSCLE to dilate blood vessels
enhanced sodium excretion in the urine (natriuresis)
soluble guanylyl cyclase has what receptor
nitric oxide (NO)
NO plays an important role in the control of what
blood flow and blood pressure
vascular endothelial cells use NO synthase to what
cleave arginine into citrulline plus NO
Nitroglycerin relieves chest pain that accompanies inadequate blood flow to the heart muscle how
breaks down and releases NO
(relaxes the smooth muscles of peripheral arterioles)
(reduces the work of the heart and relieving the associated pain)
how does viagra work
inhibits PDE5 (PDE5 stops cGAMP which stops increased blood flow)
what does RTK phosphorylate
themselves
insulin and various growth factors interact w what type of receptor
RTK
nuclear receptors bind to specific DNA sequences called what
hormone response elements
nuclear receptors are found only in the nucleus T or F
False, can be in cytoplasm also, just eventually goes to nucleus
