copy 2 Flashcards
(7 cards)
What is the term that is used to describe a hormone having multiple effects based on the tissue that they target?
Pleiotropic effects
What is the molecule that stops cAMP’s activity?
Phosphodiesterase
What are the 4 plasma membrane receptors and 1 nuclear receptor?
What are the three types of heterotrimeric G proteins?
Gs (stimulatory) → Activates adenylate cyclase, increases cAMP
Gi (inhibitory) → Inhibits adenylate cyclase, decreases cAMP
Gq→ Activates phospholipase C, increasing DAG & IP3, leading to calcium release
How does a G protein get activated and what does it do?
A hormone binds to a GPCR which changes shape to activate the G protein
The activated G protein Dumps GDP and binds to GTP in the a-subunit, this causes the a-subunit to disconnect from the Y and B subunits which form a dimer.
The G protein then goes to adenylate cyclase and activates it, the adenylate cyclase converts ATP to cAMP
cAMP then activates PKA which can phosphorylate different things in the cell
PKA can also enter the nucleus and activate CREB which induces gene transcription
The G protein then hydrolyzes the GTP back into GDP and the a-subunit binds the b and Y dimer
What are the 5 families of monomeric G protein receptors?
(Ras (rat sarcoma virus derived), Rho (Ras homolog), Rab, Ran, and Arf
What does the phosphorylation of the L-type, RyR, phospholamban, and tropnin I cause?
L-type: Increased conductance (longer openings) which will cause increased release of Ca+2 from the SR
RyR: Increased senstivity to Ca which will cause increased release of Ca from the SR
Phospholamban: Decreased inhibtory effect on Ca uptake to the SR, causing greater uptake which helps with faster contractions
Tropnin I: Longer duration of diastole
