CFB 28: Signal Transduction 2

Gq couples hormones to ___ to generate _ second messengers.

PLC; 2

What is the cascade that activates calcium channels and protein kinase C?

E → GPCR → Gaq → PLC → IP3 + DAG

What second messengers are proudced by PLC?

IP3 and DAG

What does IP3 do?

Triggers release of Ca2+ from ER

What does DAG do?

Activates protein kinase C

What is the target of PLCβ?

Gq

Which two kinases become activated?

Protein Kinase C
Ca2+/calmodulin activated kinase (CaM kinase)

What activates Protein Kinase C?

DAG and Ca++

Is PKA self-inhibited?

No, has regulatory subunits

Calcium functions through __________.

Calmodulin

What does calmodulin do upon binding calcium?

Binds to other proteins and either inhibits or activates them (ie CaM-dependent kinase)

What activates calmodulin-dependent kinase?

Calmodulin

Phosphoinositide signaling pathways

Serotonin release by blood platelets -- epinephrine (alpha adrenergic)
Histamine secretion in mast cells -- IgG