Signals thru lipids and calcium Flashcards
True or False
Phosphorylation can only be stimulatory (positive allosteric modulator
False
Phosphorylation can be stimulatory or Inhibitory
Looking at the Glycogen Breakdown and Synthesis regulation,
What are reactions are examples of
Phosphorylation is a positive allosteric modulatory?
Phosphorylation is a negative allosteric modulatory?
Look at image
True or False
Whether phosphorylation is stimulatory or inhibitory depends on the difference between different target proteins and/or the difference between different phosphorylation sisters on the same target proteins.
True
Where does epinephrine originate?
Where do its secrets from?
What are the major targets?
What type of G alpha subunit?
Epinephrine originates and secreted from the adrenal gland
The major target is the skeletal muscle via the beta-adrenergic receptor.
Gs
What is the glucogen target site?
What type of G alpha protein is used?
Where is glucagon secreted?
Target site: Glucagon receptor in the liver
G alpha protein: Gs
Secreted by the alpha cells of the pancreas
Where is insulin secreted?
What are the major target organs?
Insulin is secreted in the pancreas
Major targets are skeletal muscle, liver, and fat.
Insulin signaling inhibits breakdown and stimulates synthesis via _______________________, the key is the action of ________________, which exerts the opposite effects as PKA/phosphorylation kinase.
Pathways of regulating existing proteins to change activity
Protein phosphatase activation
protein phosphatase PP1
What is the cycle for stimulation of Breakdown and Inhibition of Synthesis?
Name the following of the structures
Where are these structures located?
Which one of these structures is cleaved by PI-PLC and creates diacylglycerol and IP3?
- phosphatidylinositol (PI)
- PI 4-phosphate [PI(4)P]
- PI 4,5-bisphosphate [PI (4,5) P2]
These structures are located in the inner lipid monolayer of the plasma membrane.
Structure 3 forms the diacylglycerol and IP3
Where is the IP3 receptor located in the cell and its function?
Located in the ER membrane
it is an allosterically coupled ion channel increase [Ca2+] by plasma membrane entry or ER release
What are the 3 factors that are needed for full activation of PKC? Where are they located and their mechanism?
DAG (binds C1A and C1B)
Ca2+ (bind C2)
Phosphatidylserine (major membrane lipid; binds C2)
This happens inside the cell
What is a pseudosubstrate and how is this related to the regulation of protein kinases?
Psuedosubstrate resembles preferred substrate RXXS/TXR)
Binds stably within a catalytic domain (catalysis of the true substrate leads to product dissociation)
What are these tumor promoters:
Phorbol esters
and
okadaic acid?
Phorbol esters –> sufficient to activate many forms of PKC (stuck accelerator (PKC activation)).
Okadaic acid is a protein phosphatase inhibitor from marine dinoflagellate, cause diarrhea by increasing phosphorylation that leads to reduced Na+ uptake and increased Cl- secretion by intestinal cells (broken brake (PP inhibition)).
True or False
Pi can also serve as binding sites for proteins containing pleckstrin homology domains.
True
______________ -ubiquitous Ca2+ binding protein that play a key role in many Ca2+ signaling pathways.
Hints:
Likely present in all cells in all vertebrates
Three different ___________ genes in humans-all encode identical 149 a.a. proteins
100% conserved between all vertebrate species (other species also have multiple gemes)
Calmodulin (CaM)
Explain the mechanism of CamKII activation by Ca2+
