Cell Signaling

Question 1

Major receptor families for short term cellular function:

Answer 1

G protein coupled receptors &

Ion channel receptors

Question 2

Major receptor families for long term cellular function:

Answer 2

Tyrosine kinase receptors &

Nuclear (intracellular) receptors

Question 3

Name the 3 Major G protein subtypes

Answer 3

Gs = stimulatory
Gi = inhibitory
Gq

Question 4

Gs cellular mechanism

Answer 4

Increase in adenylyl cyclase–>increase in cAMP–>Protein kinase A activation

Question 5

Gi cellular mechanism

Answer 5

Decrease in adenylyl cyclase –> decrease in cAMP

Question 6

Gq cellular mechanism

Answer 6

Increase in phospholipase C –> increase in IP3, diacylglycerol –> increase in cytoplasmic Ca2+

Question 7

Describe the GPCR common structure

Answer 7

7 transmembrane alpha helical regions

Alpha, beta, and gamma subunits

Gamma subunit detaches after ligand binding to signal downstream events

Question 8

Describe ion channel common structure

Answer 8

5 protein subunits

Ligand binding allows flow of ion across membrane according to gradient

Question 9

Describe common tyrosine kinase receptors structure and function

Answer 9

Extracellular ligand binding domain & 1 transmembrane domain

Intracellular portion includes tyrosine kinase that phosphorylates other proteins on tyrosines

(i.e. JAK/STAT pathway, IGF-1 receptor)

Question 10

Describe function of nuclear receptors

Answer 10

Ligand diffuses across cell membrane to bind to receptor, inducing a conformational change

-change necessary for activation/suppression of gene transcription