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8 Cards in this Set
- Front
- Back
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General pathway for GPCR systems:
What happens in the ligand-bound receptor? What is the active form? What does it do? |
7-transmembrane G-protein --> Trimeric G-P (converting GTP to GDP) --> effector enzyme
Induces G-A subunit to release GDP and bind GTP, and separate from G-BG; G-A + GTP - release P --> G-A + GDP, which reattaches to G-BG, inactivates |
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Major classes of G-Ps? How are they different?
Major 2nd messenger molecules? Two major enzymes of protein phosphorylation? |
Gs, Gi, Go, Gq; different G-A groups
cAMP, cGMP, DAG, IP3, Ca++, NO kinases - transfers P from ATP to serines, threonine, tyrosine side chains (-OH SIDE GROUPS) phosphatases - cleaves P from AA's |
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What are the structural changes with phosphorylation?
General pathway for activation of PKA? Structure of PKA? |
(-) charges on PO3- can attract (+) charges on other AA's
ligand - GPCR --> activates Gs, adenylate cyclase --> ATP converted to cAMP --> 4 cAMP complexes with inactivated PKA, activates 2 regulatory + 2 inactive catalytic subunits |
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What does PKA do to CREB's?
Role of PKA in glycolysis? |
+P and activates - CREB binds to CREB-binding protein --> binds CRE on genome --> gene transcription
activates glycogen phosphorylase --> converts glucose to G-1-P --> GLYCOLYSIS |
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Explain cAMP amplification:
What activates soluble guanylyl cyclases? Membrane bound? |
each ligand can activate multiple GPCR --> multiple adenylate cyclase --> etc, etc
soluble - NO --> muscle relaxation membrane bound - ligands (in kidney - natriuresis, diuresis) |
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General pathway of DAG, IP3 and Ca++:
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ligand - GPCR --> Gq --> PLC activation --> cleaves PIP2 to two IP3 + DAG
DAG stays in membrane, IP3 opens Ca++ channels; Ca + DAG activates PKC |
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Arichodonic Acid pathway:
What binds to phosphorylated GPCR and terminates the signal? |
ligand + GPCR --> activates PLA2 --> releases AA from membranes
AA metabolized by LO's, COX arrestin |
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Two different examples of signal integration/cross-talk?
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Two GPCR bind to same protein - protein only activated when both active sites phosphorylatd
Two GPCR binds to two different proteins - protein only active when dimerized together |
