Answers

Question 1

What is teh difference between how scaffolds and adaptors modulate signalling repsonses?

Answer 1

scaffolds recruit signalling proteins to a particular site which can change the efficiency and specificity of enzymes an cause conformational changes that alter activity or expose certain domains whereas adaptors specifically link proteins allowing them to act on each other or in conjunction

Question 2

What is the difference between the activity og GEFs and GAPs on Ras activity?

Answer 2

GEFs catalyze the exchange of GDP for GTP whereas GAPs enhance the GTPase activity of Ras which leads to hydrolysis of GTP to GDP

Question 3

What enzyme catalyses generation of PIP3 from PIP2?

Answer 3

PI-3 kinase

Question 4

What enzyme cleaves PIP2 to produce DAG and IP3?

Answer 4

PLCy

Question 5

What pathway is Ras involved in?

Answer 5

MAPK pathway- cellular proliferation

Question 6

What pathway is cdc42 involved in?

Answer 6

WASp- actin polymerisation

Question 7

What pathway is Rap1 involved in?

Answer 7

LFA-1 aggregation and cellular adhesion

Question 8

What pathway is Rheb involved in?

Answer 8

mTOR and cellular metabolism

Question 9

What does mono and di ubiquitination of surface receptors lead to?

Answer 9

recognition by ubiquitin binding proteins that target the receptor for degradation in lysosome

Question 10

What is the difference between the inhibtory pathways of PD-1 and CTLA-4?

Answer 10

PD-1 contains ITIMs that recruits SHP and SHIP upon ligand binding whereas CTLA-4 competes for costimulatory molecules and sequesters them away from CD28

Question 11

What receptor is responsible for the inhibitory action of IVIG on B cells- which must have sialic acid?

Answer 11

CD22- inhibitory receptor that binds sialic acid-containing glycoproteins