Insulin Signalling Flashcards Preview

Regulatory Physiology and Pharmacology > Insulin Signalling > Flashcards

Flashcards in Insulin Signalling Deck (36):
1

What are the three main actions of insulin?

stimulates glucose uptake into the cell
turns off glucose production after a meal
stimulates glucose storage as glycogen

2

What are some major diseases of signalling?

T2DM
heart disease
obesity
immune disease
neurodegeneration
cancer
epilepsy

3

Why is intracellular communication important?

allows cells to respond to the environment and adjust to state of cell or tissue

4

What type of receptor is the insulin receptor?

tyrosine kinase receptor

5

How are the a and b subunits connected in the tyrosine kinase receptor?

di-sulphide bridges

6

How are receptor tyrosine kinases defined?

by their ligands

7

What type of second messenger does insulin primarily use?

lipids

8

What does PI3K do?

specifically phosphorylates 3 position of ring on phosphatidyl-inositol

9

what is the major PI3K reaction involved in insulin and GF signalling?

PIP2 to PIP3

10

What does PTEN do?

convert PIP3 to PIP(4,5)2

11

What does SHIP do?

convert PIP3 to PIP(3,4)2

12

What does PIP3 activate?

Akt

13

What does Akt activate?

fuel metabolism and storage
growth
proliferation
survival

14

Where does PIP3 bind?

pleckstrin homology domains in proteins and alters their function

15

Where can proteins get phosphorylated?

serine
threonine
tyrosine
on the hydroxyl groups

16

What does protein phosphorylation do?

induce a large negative charge onto the structure

17

What is the effect of protein phosphorylation

enzyme activation/inhibition
interaction with other proteins
cellular localisation
stability

18

Give some examples of protein kinases that are oncogenes

Raf, Akt, abl

19

What are the two pathways involved with insulin action?

PI3K pathway
MAPK pathway

20

What are the two pathways involved with insulin action?

PI3K pathway
MAPK pathway

21

What does PIP3 activate?

PDK1 - tyrosine kinases, adaptor proteins, GTPases, GDP/GTP exchange

22

What does PDK1 activate?

PKB, p70S6K, PKC and SGK

23

How is PKB activated?

phosphorylated on Thr308 by PDK1 and on Ser473 by mTORC2

24

How many isoforms of PKB are there?

3

25

What does IRS activate in the MAPK pathway?

Grb2/mSOS

26

What does Grb2/mSOS activate?

stimulates Ras-GDP for Ras-GTP exchange

27

What does Ras-GDP for Ras-GTP exchange do?

activates Raf

28

What does Raf activation do?

Activates MAPKKinase

29

What does phosphorylation of MAPKK do?

activates p42/p44 MAPK

30

What does p42/p44 MAPK signalling aid in?

neuronal structure
Gene transcription and growth

31

What does PKB activation result in?

gluconeogenic inhibition
GSK3 phosphorylation
phosphorylation of p70S6K
GLUT 4 translocation

32

What turns off insulin signalling?

MAPK phosphatase

33

What kinds of treatments are being looked at for insulin resistance in diabetics?

PTP-1B inhibitors
GSK3 inhibitors
AMPK activators

34

How would GSK3 inhibitors work?

artificially restore the effect of insulin

35

What does reduced insulin sensitivity result in?

increased insulin production to compensate

36

What are some complications of T2DM?

retinopathy
neuropathy
nephropathy
stroke
heart failure