Cell Regulation

Question 1

What are the types of membrane receptors?

Answer 1

• GPCR
• Tyrosine Kinase
• JAK Kinase
• Ser/Thr Kinase
• Guanylate cyclase
• Ion Gated

Question 2

What is characteristic of Diabetes Insipidus?

Answer 2

• Deficiency in ADH action
• Neurogenic: No functional ADH
• Nephrogenic: No functional ADH response due to mutation in V2-R or AQ2

Question 3

What type of receptor is the V2 receptor (ADH)?

Answer 3

GPCR

Question 4

What are the components of the GPCR?

Answer 4

• alpha
• beta
• gamma

Question 5

What action happens after stimulation of the alpha subunit by an external stimuli?

Answer 5

• alpha(s) subunit stimulates adenyl cyclase to increase cAMP

Or

• alpha (i) inhibits adenylyl cyclase and therefore decreases cAMP

Question 6

How does the pertussis toxin affect intracellular signaling pathways?

Answer 6

B. pertussis secretes pertussis toxin,
which ADP ribosylates the αi subunit which inactivates αi, and reduces the inhibition of
adenylyl cyclase

Question 7

What affect does activation of alpha (q) subunit have?

Answer 7

• Activates PLC, which cleaves PIP2 to become IP3 and DAG

Question 8

Which factor is stimulated by the V2 receptor pathway to enter the nucleus and stimulate gene activation resulting in an increase in AQ2 insertion?

Answer 8

CREBP

Question 9

What second messenger system is activated by the V2 vasopressin receptor?

1. G alpha-s stimulation of adenylate
cyclase 
2. G alpha-i inhibition of adenylate
cyclase 
3. Tyrosine kinase 
4. Guanylate cyclase 
5. Gq stimulation of phospholipase C

Answer 9

1. G alpha-s stimulation of adenylate

cyclase

Question 10

What type of receptor is the insulin receptor?

1. G protein associated receptor
2. Tyrosine kinase
3. Receptor associated with a JAK tyrosine kinase
4. Guanylate cyclase
5. Ion channel

Answer 10

2. Tyrosine kinase

Question 11

What mutation occurs to CFTR in CF patients?

Answer 11

508del of Phe

• Transporter does not reach plasma membrane due to defect leading to symptoms

Question 12

What is the pathway of Insulin from DNA to exocytosis?

Answer 12

Regulated Insulin Secretion Pathway
DNA → transcription → hnRNA processing and exon splicing → mRNA → ribosome → docking to the RER → Protein synthesis and processing at RER → Transport to Golgi → Processing, sorting and packaging into
vesicles by Golgi → Vesicles transported
along microtubules (kinesins & dyneins) → Cytoplasmic Ca++ increases → Exocytosis

Question 13

What are the two calcium-activated receptors?

Answer 13

• IP3R

- Ryanodine

Question 14

What are common 2nd messengers of GCPRs?

Answer 14

• cAMP
• cGMP
• IP3
• DG/DAG
• Ca++

Question 15

Describe the affect of Epinephrine on secondary messengers.

Answer 15

EP binds GCPR alpha-2 receptors, which contain a alpha-i subunit which bind adenylyl cyclase and inhibit cAMP.

Question 16

How does ADH affect smooth muscle contraction?

Answer 16

• ADH binds V1 receptors (GCPR) -> Gq -> PLC -> IP3 + DAG
• IP3 -> ER Ca++ release
• DAG + Ca++ -> PKC -> Protein phosphorylation -> Smooth muscle contraction

Question 17

What type of receptor is the insulin receptor?

1. G protein associated receptor
2. Tyrosine kinase
3. Receptor associated with a JAK tyrosine kinase
4. Guanylate cyclase
5. Ion channel

Answer 17

Tyrosine kinase

Question 18

Differentiate Constitutive and regulated secretion.

Answer 18

Constitutive secretion – transport and
secretion of substances immediately
following regulated synthesis

Regulated secretion – substances to be
secreted are stored in granules or
vesicles prior to release

Question 19

What stimulates regulatory exocytosis?

Answer 19

• Entry of Ca++ into the cytosol f/ exterior

- interaction of proteins such as SNARE complexes

Question 20

What cell functions are regulated by calcium?

Answer 20

• Regulatory proteins (calmodulin, troponin)
• Enzymes (NO synthase)
• Membrane depolarization
• Secretion