Transmembrane receptor enzyme

Question 1

What are the 3 classes of Transmembrane receptor enzyme

Answer 1

Receptor tyrosine kinase, receptor ser/thr kinase, receptor guanylyl cyclase

Question 1

Exp of recep tyrosine kinase

Answer 1

Epidermal Growth Factor Receptor

Question 2

Exp of recep ser/thr kinase

Answer 2

Transforming Growth factor-B (TGF-B)receptor, Bone Morphogenetic Protein (BMP) receptor

Question 3

Exp of recep guanylyl cyclase

Answer 3

Natriuretic Peptide receptor (NPR) (GC-A ,GC-B) , GC-C receptor

Question 4

Examples of Receptor Tyrosine Kinase activation pathway

Answer 4

EGFR as Exp
Pathways: PLCy , PI3-K, MAPK

Question 5

What happen when ligand binds to Recep tyrosine kinase

Answer 5

• Two monomers form inactive homodimer
• Cross-phosphorylation of homodimer
• SH2 domain protein binds to Tyr

Question 6

What happen when PLCy binds to Tor on recep tyr kinase

Answer 6

• PIP2 breakdown into DAG + IP3
• DAG activates PKC, IP3 binds to recep on ER, ER releases Ca

Question 7

What happen when P13K pathway activated

Answer 7

• PI-3 kinase phosphorylates PIP2 to PIP3
• PDK1 activates by PIP3, followed by activation of PKB(Akt)
• apoptosis inhibited, cell proliferation

Question 8

What happen in MAPK pathway

Answer 8

• Grb2 binds to Tyr on recep
• Activate Ras GDP/GTP exchange
• Raf, Mek , Map kinase activation
• Gene transcription

Question 9

Drug to inhibit EGFR

Answer 9

Gefitinib

Question 10

Drug to inhibit VEGFR

Answer 10

anti-VEGF mAb (Ranibizumab)

Question 11

How Recep Ser/Thr activated?

Answer 11

TGF-B binds to Type-II receptor, Type-II homodimer phosphorylates type-I homodimer form heterotetramer

Question 12

What is R-Smad?

Answer 12

Transcription factor activated by TGF-B receptor heterotertramer

Question 13

How many domains Smad has?

Answer 13

MH1 & mh2

Question 14

role of MH2?

Answer 14

Interact with receptor ser/thr kinase

Question 15

role of MH1

Answer 15

DNA binding domain

Question 16

rhBMP full form?

Answer 16

Recombinant human bone morphogenetic Protein

Question 17

Drug for long bone nonunion

Answer 17

rhBMP-7

Question 18

Role of activin receptor Type IIB-Fc Fusion Protein

Answer 18

Treat anaemia in B-thalassemia

Question 19

Role of activin receptor Type IIA-Fc Fusion Protein

Answer 19

Treat pulmonary arterial hypertension

Question 20

Role of receptor guanylyl cyclase

Answer 20

converts GTP to cGMP, cGMP then activate PKG

Question 21

Ligands of NPR-A (GC-A)

Answer 21

ANP , BNP

Question 22

Ligands of NPR-B (GC-B)

Answer 22

CNP from endothelial and renal cells

Question 23

Ligands of clearance receptor (NPR-C)

Answer 23

ANP, BNP and CNP

Question 24

Ligands for GC-C

Answer 24

Uroguanylin , guanylin

Question 25

Location of GC-A,B & C?

Answer 25

cardiovascular system, skeletal system, GI tract respectively

Question 26

Location of GC-E & GC-F

Answer 26

retinal photoreceptors

Question 27

Pharmacological effects when GC-A activated

Answer 27

• Natriuretic,
• arterial vasodilation,
• renin & aldosterone suppressing
• Anti-hypertrophic

Question 28

Pharmacological effects when GC-B activated

Answer 28

• Anti-fibrotic
• Anti-inflammatory

Question 29

Drug to activate GC-A and GC-B (agonist)

Answer 29

Cenderitide

Question 30

GC-C agonist for chronic idopathic constipation

Answer 30

Linaclotide

Question 31

What happen when GC-C activated?

Answer 31

• GTP > cGMP
• cGMP activate PKGII
• promotes Cl- and HCO3- ions secretion from gut cells
• retain Na+ and H2O in lumen