8: Cell Communication 2

Question 1

Describe the signal transduction through DAG and Ca2+

Answer 1

G protein complex
-Gαq

Effector
-Phospholipase C(PLC)

Second messenger
-DAG, IP3, Ca2+

Cellular effect
-Activate PKC, regulate Ca2+ binding proteins

Question 2

Describe the GPCR example of rod cells in retina in detection of light

Answer 2

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Question 3

How does cholera toxin affect G protein signalling pathway?

Answer 3

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Question 4

How does pertussis toxin affect G protein signalling pathway

Answer 4

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Question 5

What are ways in which GPCR signal transduction pathways can be switched off?

Answer 5

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Question 6

Describe the signalling pathways of enzyme-linked receptors

Answer 6

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Question 7

What are the different types of enzyme-linked receptor? (4)

Answer 7

• Guanylyl cyclases
• Serine/theorine kinases
• Tyrosine kinase receptors
• Tyrosine kinase associated receptors

Question 8

Describe/draw out guanylyl cyclases

Answer 8

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Question 9

Describe/draw out serine/theorine kinases

Answer 9

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Question 10

Describe/draw out tyronsine kinase receptors

Answer 10

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Question 11

Describe/draw out tyrosine kinase associated receptors

Answer 11

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Question 12

What are the three types of nitric oxide synthase (NOS)

Answer 12

• Nnos (neuronal nos) for nervous system
• iNos for inducible tissue/immune (in macrophages -in smooth muscle)
eNos for endothelia (for your blood vessels)

Question 13

Production of nNOS

Answer 13

Arginine –> nNOS –> nitric oxide

Question 14

Production of iNOS

Answer 14

NADPH –> iNOS –> NADP

Question 15

Production of eNOS

Answer 15

O2–> eNOS –> Citrulline

Question 16

How does eNOS promotes blood vessel dilation

Answer 16

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Question 17

What are the synaptic functions of nNOS

Answer 17

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Question 18

What receptor can Guanylyl cyclase have

Answer 18

Guanylyl cyclases can either be transmembrane receptors (e.g. atrial natriuretic peptide (ANP) receptor), OR cytoplasmic enzymes (NO)

Question 19

What chemical reaction does Guanylyl cyclase catalyse?

Answer 19

GTP —–> cGMP

Question 20

What is the second messenger for Guanylyl cyclase?

Answer 20

cGMP is a second messenger that diffuses through the cytoplasm and then activates protein kinase G.

Question 21

What receptor does a serine/theorine kinase have?

Answer 21

Ligands such as TGFβ (transforming growth factor β) bind a receptor that contains a serine/threonine kinase domain