Powerpoint 4 Chapter 14 Flashcards
epinephrine receptor
beta-andrenergic
epinephrine causes
energy-store mobilization
insulin causes
increased glucose uptake
EGF causes
expression of growth-promoting genes
signal transduction steps
1) release of primary messenger 2) reception of primary messenger 3) transduction. receptor releases second messengers 4) Activation of effectors 5) termination
effector
controls channels or pumps, enzymes, or proteins that control gene expression
common second messengers
cAMP, Ca++, inositol, DAG
three receptor types of signalling pathways
G-protein coupled, enzyme linked, ligand gated ion channels
enzyme linked receptors have ? or ? activity
cytoplasmic tyrosine kinase, guanylyl cyclase
G-protein receptors AKA
7-transmembrane helix receptors
7TM receptors only found in ?
eukaryotes
first member of the 7TM family discovered
Rhodopsin
?% of therapeutic drugs target 7TM receptors
50
bind to andrenergic receptors to activate
agonists
inhibit actvation
antagonists
types of andrenergic receptors
alpha 1 and 2, beta 1,2 and 3
consequence of ligand binding to 7TM
conformational change converts receptor into a guanine nucleotide exchange factor. activation of G protein trimer (of alpha, beta, and gamma subunits) because the alpha subunit binds guanyl nucleotides causes the alpha subunit to dissociate.
activation of adenylate cyclase by alpha subunit of G-protein causes
conversion of ATP into cAMP
beta-andrenergic receptor is a type of ?
7TM receptor
epinephrine binding to beta-andrenergic receptor resulting pathway
activation, conformatinal change. activation of G-protein and dissociation of alpha subunit. protein interaction with adenylate cyclase activates. enzymatic reaction to form cAMP. activated protein kinase A.
pathway linking activated Protein Kinase A to mobilization of stored CHO
PKA activates phosphoryl kinase. phosphoryl kinase activates phosphorylase. phosphorylase initiates synthesis of glucose from glycogen.
four ways of regulating signaling
at the receptor (agonist/antagonist, desensitization), the g-protein itself, second messenger, protein kinases
receptors turned of by?
dissociation of signal molecule
receptors desensitized by?
phosphorylation of cytoplasmic C-terminal and binding of b-arrestin
G-proteins are timers because..
they turn off by hydrolyzing GTP to GDP and Pi
cAMP is degraded by
soluble phosphodiesterase
ACE inhibitors are important for?
lowering blood pressure