GPCR

Question 1

What is the structural components of GPCR

Answer 1

receptor, G protein, effector

Question 2

Which receptor formoterol targets at?

Answer 2

It is B2 adrenergic Gas agonist (anti-asthma)

Question 3

Which receptor clonidine targets at?

Answer 3

It is Gi agonist

Question 4

Which receptor phenylephrine targets at?

Answer 4

It is a1 adrenergic Gq agonist (nasal decongestant )

Question 5

What is the role of phosphodiesterase (PDE)?

Answer 5

breakdown cAMP/cGMP (depends on its subtype)

Question 6

Describe transducin signalling pathway

Answer 6

• Photon binds to rhodopsin > conformational change
• Rhodopsin activates transducin (Gat)
• Transducin activates PDE V
• PDE V degrades cGMP
• Drop in cGMP inactivates Na+/Ca++ channel
• Rod cell hyperpolarization & send signal to brain
• Drop in Ca activates cytosolic guanylyl cyclase (increases cGMP)
• re-open Na+/Ca++ ion channel
• Photoreceptor signalling starts again

Question 7

What happen when Gaq is activated

Answer 7

Phospholipase C is activated

Question 8

What happen when PLC activated?

Answer 8

breakdown Phosphatidylinositol-4,5-bisphosphate (PIP2) into Diacyclgrlcerol (DAG) & Inositol 1,4,5-Triphosphate (IP3)

Question 9

What is role of IP3

Answer 9

Activate Ca++ ion channel on ER to release Ca++, Ca++ binds to Calmodulin for signalling response

Question 10

What does DAG do?

Answer 10

Activate prot. kinase C tgt w Ca++

Question 11

Types of GPCR regulation

Answer 11

Ligand removal, desensitisation

Question 12

Steps of desensitization

Answer 12

Uncoupling , Internalisation , down-regulation

Question 13

Role of GRK

Answer 13

Phosphorylate GPCR , allow arrestin to bind for desensitisation and internalisation Or down-regulation (breakdown receptor)

Question 14

types of desentization

Answer 14

Homologous , heterologous

Question 15

What is homologous desensitisation?

Answer 15

GPCR inactivated by GRK phosphorylation, arrestin binds to it

Question 16

What is heterologous desensitisation

Answer 16

Phosphorylation by PKA,PKC inactivation

Question 17

Tm for osteoporosis?

Answer 17

Calcitriol (VDR agoinst), Raloxifene (ER agonist)

Question 18

What is the use of Mifepristone

Answer 18

Progesterone receptor antagonist, induce abortion

Question 19

Glucocorticoids for?

Answer 19

GR agonist, anti-inflammatory

Question 20

Drug for prostate cancer?

Answer 20

Apalutamide, AR antagonist

Question 21

Drug for breast cancer?

Answer 21

Tamoxifen , PR antagonist

Question 22

Tm for Type-II diabetes mellitus

Answer 22

Rosiglitazone (PPARy agonist)

Question 23

Tm for acne (topical)

Answer 23

Tretinoin (RAR agonist)

Question 24

Modes of nuclear receptor activation

Answer 24

• Genomic, Tethered, non-genomic, ligand-independent

Question 25

Type of nuclear receptor

Answer 25

Class I, hybrid, Class II

Question 26

Diff btw Class I & II nuclear receptor

Answer 26

- Class I found in cytoplasm, II in nucleus - I operates as homodimers, II as heterodimers - I high affinity , II low affinity

Question 27

Examples of Class II nuclear receptors

Answer 27

peroxisome proliferator-activated receptor (PPAR), Aryl hydrocarbon receptor (AhRe)

Question 28

Thyroid receptor is which type of nuclear receptor?

Answer 28

Hybrid receptor

Question 29

Exp of Class I steroid receptor

Answer 29

GR, ER, MR, PR ,AR

Question 30

Structure of nuclear receptor

Answer 30

Ligand-binding domain, DNA-binding domain, Transcription-activating domain

Question 31

PPAR full form?

Answer 31

Peroxisome proliferator-activated receptor