Lecture 4 - Intracellular signalling

Question 1

At the level of gene transcription and protein translation, what causes signalling in muscle?

Answer 1

Mechanical load

Hormonal adjustment

Neuronal activation

Metabolic disturbance

Question 2

describe Ca2+ - calmodulin (CaM) signalling in muscle

Answer 2

increase in calcium when muscles depolarise - Ca2+ combines with a protein called calmodulin and there is a kinase (cAMP kinase) - there are various isoforms of this kinase but the most predominant one is cAMP 2

Question 3

Generally speaking, what does CAMKinase 2 have the ability to modify?

Answer 3

modify other proteins

modify the nucleus to change gene expression - part of the adaptive response

Question 4

CaM can also target phosphorylase kinase causing?

Answer 4

glycolysis, but also turns off protein synthesis

after exercise this is reversed, which helps recovery

Question 5

Exercise ______ Calcium-calmodulin-dependent protein kinase activity in human skeletal muscle

Answer 5

increases

Question 6

AMP-activated protein kinase is activated by …

Answer 6

AMP - an energy sensor

Question 7

What are the effects of AMP-activated protein kinase on the heart?

Answer 7

stimulates: glucose uptake, glycolysis, FA oxidation

Question 8

What are the effects of AMP-activated protein kinase on the hypothalamus

Answer 8

stimualtes Food intake

Question 9

What are the effects of AMP-activated protein kinase on the skeletal muscle

Answer 9

stimualtes FA oxidation, glucose uptake, expression of GLUT4, MItochondria

Question 10

What are the effects of AMP-activated protein kinase on the adipose tissue

Answer 10

Inhibits: FA synthesis, lipolysis

energy consuming pathways

Question 11

What are the effects of AMP-activated protein kinase on the Liver

Answer 11

Inhibits: FA synthesis Cholesterol synthesis, Gluconeogenesis

Question 12

What are the effects of AMP-activated protein kinase on the Pancreas

Answer 12

inhibits Insulin secretion

Question 13

Activation of the other metabolic pathways is very good at…

Answer 13

maintaining ATP levels

Question 14

AMPK activity is directly correlated with…

Answer 14

the exercise intensity

Question 15

How is GLUT 4 expression increased during exercise?

Answer 15

When muscle contract they consume energy

they break down ATP, creatine P, glyocgen - which gives you an inccrease in AMP = > this activates AMP-kinase

Ca2+ increase also activates CaM Kinase 2

These two enzymes can phosphorylate a transcriptional repressor which comes out of the nucleus, the transcriptional factor (MEF2) binds to the GLUT 4 promoter and increases GLUT transcription/translation

Question 16

CaM Kinase 2 and AMP-kinase are not only involved in the acute response to exercise but also the ______ part

Answer 16

adaptive

Question 17

ROS can do what in muscles?

Answer 17

Increase kinase activity

Cause gene transcription

decrease phosphatase activity

Question 18

What signalling pathways increase muscle mass?

Answer 18

mTOR - stimulates protein synthesis

Question 19

is mTOR activates during exercise?

Answer 19

No, only in recovery

protein synthesis goes down during exercise

Question 20

If you increase your protein intake, you increase you’re?

Answer 20

protein synthesis

Question 21

AMPK will decrease some of the effects of…

Answer 21

MTOR