mechanism of action of insulin
TRANSCRIPT
What are the types of receptors?
What are the examples of ligands acting by tyrosine
kinases?
What are the various actions of insulin apart from
transporting glucose?
The student should be able to recall –
The structure of tyrosine kinase receptor.
How insulin mediates its anabolic effects.
How insulin helps the cell take up glucose.
Substrate – tyrosine residues present on the activation
segment of the opposite dimerized enzyme.
Transfers PO4 group from the γ PO4 of ATP.
prosthetic group – Mg ion.
INOSITOL INOSITOL 3 PO4
INOSITOL 4 PO4 INOSITOL 3,4 BIS PO4
INOSITOL 4,5 BIS PO4INOSITOL 3,4,5 TRIS
PO4
protein
Kinase B
Inositol 3,4 bis PO4
TSC 2
Rheb
mTOR
Rheb
E-BP
e IF
e IF – eukaryotic initiation factor
E-BP – e IF binding protein
Translation
e IF
mTOR-mammalian target of rapamycin
Rheb – Ras homologue enriched in brain
Activates Hexokinase
Glycogen synthase
Pyruvate dehydrogenase
Acetyl CoA caboxylase
Inhibits
Glycogen phosphorylase
The gluconeogenesis
enzymes that reverse
glycolysis
Hormone sensitive lipase
Nucle
us
Plasma
membrane
Microtubular
Meshwork
GLUT 4
Actin meshwork
Actinin 4
Docking and fusion-
SNARE protein.
Insulin
Whats the first thing that happens to insulin receptor
when insulin binds to it?
1. Dimerization
2. Bridging of the tyrosine kinase domains
3. Activation of protein kinase B
The completely phosphorylated intracellular portion of
insulin receptor acts as a docking site for?
1. mTOR
2. IRS
3. GLUT 4
How does insulin affect GLUT 1 vesicles?
1. Brings them to the surface.
2. Increases synthesis of GLUT 1 mRNA.
3. No effect.