Fast Hormonal Signal Transduction Processes (2) Flashcards
What is the structure of PKA?
R2C2 heterotetramer - 2 regulatory subunits, 2 catalytic subunits
What type of kinase is PKA?
Serine/threonine kinase
How many molecules of cAMP bind to each regulatory subunit to cause dissociation from the catalytic subunits?
2 - 4 per PKA
Which enzyme breaks down cAMP to AMP?
Cyclic nucleotide phosphodiesterase
What is beta-ARK?
GPCR kinase
What does beta-ARK bind to?
Beta-gamma subunit of G-protein
What is the effect of beta-ARK?
Phosphorylates receptor C-terminus - creates binding site for beta-arrestin
What is the effect of beta-arrestin?
Blocks intracellular loops of receptor - cell cannot respond to receptor stimulation
What is the effect of PLC?
Breaks down PIP2 - forms hydrophobic DAG and hydrophilic IP3
What type of kinase is PKC?
Serine/threonine kinase
What type of kinase is the EGF receptor?
Receptor tyrosine kinase
What is the effect of EGF receptor?
Activates transcription factors - causes cell growth - long-term effect
What is Grb-2?
Adaptor protein
What is Sos?
GEF
What is Ras?
Monomeric G-protein
What increases the GTPase activity of Ras?
GTPase activating proteins (GAPs)
What type of kinase is the insulin receptor?
Receptor tyrosine kinase
How do PKB and PDK1 bind to PIP3?
Pleckstrin homology domains
What are the effects of the insulin receptor?
Short-term - GLUT4 translocation
Long-term - via Grb-2 binding to IRS-1 - activates MAPK pathway
