Exam 2 Signaling Cascades Flashcards
what is the second messenger of epinephrine B2 adrenergic receptor signaling cascade and glucagon glucagon receptor signaling cascade?
cAMP
what generates cAMP?
adenylyl cyclase
what are the subunits of G proteins?
alpha, beta, gamma
what kind of alpha subunit do Gs family proteins have?
stimulatory
Gs family protein result
increase cAMP production
why does the Gs family protein increase cAMP production?
it stimulates adenylyl cyclase which then generates cAMP
what G-protein family pathway do epinephrine and glucagon work through?
Gs
what kind of alpha subunits do Gi family proteins have?
inhibitory
Gi family protein result
decrease cAMP production
why does the Gi family protein decrease cAMP production?
it inhibits adenylyl cyclase or it activates phosphodiesterase
what does the Gq family protein do?
activates phospholipase C
what does the G12/13 family protein do?
activates Rho GTPase which is involved in cytoskeletal dynamics, organelle generation, etc.
what catalyzes ATP to cyclic AMP?
adenylyl cyclase
what catalyzes cyclic AMP to AMP?
phosphodiesterase
what catalyzes phosphotidylinositol-4,5-biphosphate (PIP2) to diacylglycerol and inositol-1,4,5-triphosphate (IP3)
phospholipase C
what catalyzes phosphotidylinositol-4,5-biphosphate (PIP2) to phosphotidylinositol-3,4,5-triphosphate (PIP3)
phosphoinositide-3-kinase (PI3K)
what is the ratio of Protein Kinase A catalytic and regulatory subunits?
2 catalytic subunits : 2 regulatory subunits
what do the Protein Kinase A regulatory subunits have?
two cAMP binding sites (4 cAMP bind to the 2 regulatory subunits)
what occurs when two cAMP bind to the 2 regulatory subunits of Protein Kinase A?
the catalytic subunits are freed so they can phosphorylate targets
what are the secondary messengers of the epinephrine alpha 1 adrenergic receptor signaling cascade?
diacylglycerol and inositol triphosphate (IP3)
diacylglycerol in the epinephrine signal cascade
second messenger that activates Protein Kinase C
inositol triphosphate (IP3) in epinephrine signal cascade
polar, doesn’t associated with membrane
activates Ca2+/CAM
what are the primary kinases of the epinephrine signaling cascade?
Protein Kinase C and Ca2+/Calmodulin Protein Kinase (Ca2+/CAM)
what G-protein-coupled receptor G-protein family does epinephrine to phospholipase Cbeta use?
Gq
what does epinephrine activate?
phospholipase Cbeta
what occurs after epinephrine activates phospholipase Cbeta and 2nd messengers are generated?
we activate kinases; goal is to metabolic targets
what is the insulin receptor an example of?
a receptor tyrosine kinase
what are the two major pathways in insulin receptor signaling (IRS-1)?
Ras (GDP/GTP Exchange) MAP Kinase Cascade
and PI3K
what occurs when insulin receptor signaling activates PI3K?
PI3K generates PIP3 and the effects are mediated my Protein Kinase B
what kinase does PI3K activate?
protein kinase B
what are the primary metabolic targets of Protein Kinase B?
- cardiomyocytes PFK2/FBPase-2
- glycogen synthase kinase (hepatocytes and skeletal myocytes)
- PPP-1 regulatory subunit
- phosphodiesterase 3beta isozyme (degrades cAMP)
- FOXO-1
what occurs when the insulin receptor signaling activates the Ras/MAPK Cascade?
MAPK, MAP2K, MAP3K
mostly related to gene expression
