Chapter 11: Lymphocyte Activation

Question 1

ITAM’s

Answer 1

Signalling subunits

Phosphorylation by Src (lck) leads to TCR activation

Question 2

Src family kinase

Answer 2

E.g. lck

Phosphorylate ITAM’s which leads to TCR activation

Question 3

Csk

Answer 3

C terminal src kinase

Phosphorylation of Lck (blocks SH2 domain) which leads to its inactivation

Question 4

CD45

Answer 4

Phosphatase which removes phosphate from lck and leads to its activation

Question 5

Tyrosine 505

Answer 5

Blocks the active site of SH2 domain on lck

Question 6

Tyrosine 394

Answer 6

Phosphorylation leads to open SH2 domain

Question 7

Lck

Answer 7

A src family kinase which phosphorylates ITAMS

Also phosphorylates ZAP70

Question 8

ZAP70

Answer 8

Syk family kinase
Recruited to ITAM of CD3Zeta
Phosphorylates LAT and PLCGamma

Question 9

LAT

Answer 9

When phosphorylated by Zap70 acts as a docking site
Phosphortylated tyrosines are the docking site
Leads to PLC pathway (NFkB, NFAT) and MAP kinase pathway

Question 10

PLCGamma

Answer 10

Activated by Zap 70 and Itk
When cleaved leads to DAG and IP3
Leads to PLC pathway resulting in NFkB or NFAT

Question 11

IkB kinase

Answer 11

Phosphorylates NFkB/IkB compex which leads to dissociation of IkB and allows NFkB to be translocated to nucleus

Question 12

PKC

Answer 12

Protein kinase C

Product from DAG which leads to recruitment of IkB kinase which dissociates IkB/NFkB compex

Question 13

DAG

Answer 13

Formed from the cleavage of PLC Gamma

Question 14

IP3

Answer 14

Formed from cleavage of PLC gamma and leads to NFAT transcription factor activation
Mobilises calcium stores required to activate calcineurin

Question 15

Calcineurin

Answer 15

Phosphatase which removes phosphate from inactive NFAT
Attached to Calmodulin and is activated which Ca2+ binds to calmodulin
Allows NFAT translocation to nucleus

Question 16

Ras

Answer 16

G protein which is activated by SOS

GDP to GTP

Question 17

Guanine nucleotide exchange factor

Answer 17

SOS

Turns G protein GDP to GTP

Question 18

RAF

Answer 18

Map kinase kinase kinase

Question 19

Mek

Answer 19

MAP kinase kinase

Question 20

Erk

Answer 20

MAP Kinase

Question 21

Elk

Answer 21

An activated transcription factor in MAP pathway which when activated leads to AP-1 production

Question 22

Grb-2

Answer 22

Attaches to LAT and allows SOS to bind