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Flashcards in Insulin Deck (13):
1

Insulin key proteins

1) Glut4
2) Protein Kinase B (PKB)
3) Protein Phosphatase 1 (PP1)
4) Glycogen Synthatase Kinase 3 (GSK3)

2

Signaling cascade involving insulin

Insulin-receptor, activating PKB
GLUT translocates to membrane
PKB activates PP1
PKB inactivates GSK1

PP1 activates Glycogen synthase
PP1 inactivates glycogen phosphorylase

3

PKB

activates PP!, inactivates GSK3

4

PP1

activates Glycogen synthase
inactivates glycogen phosphorylase

5

What does a mutated insulin receptor cause

causes PP1 to inactivate glycogen phosphorylase and inactivate pyruvate kinase: glycogen is not released from liver

6

high blood glucose leads to

high insulin, stimulates glycogen synthase

insulin to receptor--> activation of PKB --> GLUT translocation, PPI activation/GSK3 inactivation

PPI activates glycogen synthase

7

low blood glucose leads to

high glucagon, stimulates gluconeogenesis and glycogenolysis


8

glucagon is released from ___ cells: what enzymatic cascade occurs

1. alpha cells


glucagon binds to GCMP-->adenylate cyclase --> cAMP

cAMP activates Protein kinase A
PKA inactivates Glycogen synthase Oka inhbits PP1
PKA phosphorylates activate

PK activates glycogen phosphorylase

pathway defective in type II diabetes

9

glucagon's ultimate outcome i

inactivation of glycogen synthetase and activation of glycogen phosphorylase

10

glucagon enzyme cascade sequence

glucagon--> GPCR --> adenylate cyclase--> cAMP --> PKA-->inactivation of PPI and glycogen synthase, activates PK which activates glycogen phosphorylase

11

other regulatory mechanisms of glycogen break down/synthesis

epinephrine: fight or flight response
breakdown of glycogen
PW similar to glucagon

allosteric inhibitors
Glucose 6 phosphate - activates glycogen synthase, inactivates glycogen phosphorylase

12

glucose 6 phosphate

allosterically stimulates glycogen synthase
inactivates glycogen phosphorylase

13

free glucose

allosteric inhibitor of glycogen phosphorylase in liver but not muscle