Signal transduction Flashcards
Sympathetic Catecholamines
Epinephrine, norepinephrine
Parasympathetic esters
Acetylcholine
Excitatory Amino Acid Neurotransmitters
Glutamine, aspartate
Inhibitory Amino Acid Neurotransmitters
GABA, Glycine
Most common class of receptors
G-protein coupled recetors
Action of G-proteins
Pass the signal from receptor proteins to effector proteins, releasing 2nd messengers
Second messengers produced by G-protein activation
cAMP, IP3, DAG, Ion channel activity
Subunits of G-proteins
Alpha, beta, gamma
G-protein Alpha subunit
Activation alters 2nd messenger levels, can open ion channels
Family that cAMP belongs to
Adenylate Cyclase (membrane spanning enzymes)
What stimulates adenylate cyclase?
Gs-type G-proteins (and their associated receptors)
What inhibits adenylate cyclase?
Gi-type G-proteins (and associate receptors
How does cAMP exert its effect?
Activates protein kinase A (PKA)
What is PKA’s action?
Phosphorylates proteins (enzymes, pumps, channels). Can either increase or decrease activity depending on protein
Adenylate Cyclase
Family of membrane spanning enzymes (10 identified). Isoforms differ in respect to activity modulation
Kinases Activity
Phosphorylate adenylate cyclase in some cells
What protein is linked to phospholipase C activation?
Gq-mediated protein receptor
What second messengers does PLC produce?
IP3 and DAG
What is associated with PLC activation?
Ca-channel activation
Action of IP3
Binds to IP3 receptors on the ER to release the intracellular Ca stores
Action of DAG
Remains membrance associated, activates protein kinase C
Activation of PKC
Translocates from the cytosol to the membrane. PKC will phosphorylate other proteins and alter their function state
What causes IP3-mediated Ca release?
PLC
NO’s effect on cGMP levels?
Increases cGMP levels
