Lecture 9: Immune Receptors and Signal Transduction II

Question 1

CD81 is necessary for

Answer 1

Normal CD19 expression

Question 2

Ubiquitin is added to which residues by what

Answer 2

Lysine residues by E3 ubiquitin ligase

Question 3

PLC function chemokine signaling

Answer 3

PLC hydrolyzes IP2 into IP3 which mobilizes calcium

PLC activates DAG which activates protein kinase C

Question 4

Type I&2 cytokine receptors engage in what type of signaling pathway

Answer 4

JAK-STAT pathway

Type II also use Tyk-STAT pathway

Question 5

ITIMs of inhibitory receptors such as CD22/CD32 are phosphorylated by

Answer 5

Src kinase family, which are activated by B lymphocyte activation

Question 6

p-ITIMs (phosphorylated-ITIMs) recruit

Answer 6

SH2 domain containing tyrosine phosphatases such as SHP and SHIP

Question 7

Engagement of CD40:CD40L provides and results in

Answer 7

Provides co-stimulation to B cell and results in expression of IL-4R by B cells

Question 8

CD21

Answer 8

Known as complement receptor 2 CR2

Question 9

G protein alpha subunit function in chemokine receptor signaling

Answer 9

Inhibits some adenylyl cyclase leading to decreased intracellular cAMP levels

Question 10

Sykkinases phosphorylate what after activation by what

Answer 10

After activation by Src kinases, Syk kinases phosphorylate critical tyrosine residues on BLNK

Question 11

CD32 (FcyRIIB) co receptor

Answer 11

Contains an ITIM and negatively regulates BCR signaling

Question 12

Phosphorylated ITAMs on BCRs provide

Answer 12

Docking site for the tandem SH2 domains of Syk tyrosine kinase

Question 13

Type II cytokine receptors include receptors for

Answer 13

Also called interferon receptor family
IFN-a/b
IFN-y
IL-10

Question 14

SHP and SHIP function

Answer 14

Remove phosphates from PIP3 and thus inhibit PI# kinase activity

Question 15

Type I cytokine receptors

Answer 15

IL-2, 4, 7, 9, 15, 21

Question 16

There are 5 classes of cytokine receptors, what makes chemokine receptors different from the rest

Answer 16

Chemokine receptors are not single-pass transmembrane proteins

Question 17

Ag binding to BCR facilitates

Answer 17

Conformation change in BCR-associated ITAMs, making them accessible to Src kinases such as lyn, fyn and blk
-These Src kinases then phosphorylate the ITAMs of Iga and Igb

Question 18

Invariant signaling Iga and Igb molecules

Answer 18

They are disulfide linked to one another
Non covalently associated with the BCR
Contain ITAMs in their cytoplasmic domains
-ITAMs mediate signaling function

Question 19

CD19

Answer 19

Functions as the dominant signaling component of B cells

Question 20

Engagement of TLR results in

Answer 20

Dimerization and recruitment of MyD88 adaptor containing TIR domain, which link TLR/IL-1R to members of IRAK family
IRAK links adaptors to TRAF6, an E3 ubiquitin ligase required for NF-kB activation

Question 21

CD81 is important for

Answer 21

Linking the membrane CD21-CD19-CD81 complex to the cytoskeleton

Question 22

Response from BCR/CR2 complex compared with B cell response with just Ag

Answer 22

BCR/CR2 combined cascade greatly enhances the B cell activation compared to response with Ag alone

Question 23

TCR activation and CD28:CD80/86 costimulation results in

Answer 23

Secretion of IL-4 by activated T cells

Question 24

G protein b/y subunit function in chemokine signaling

Answer 24

Activates Ras that induces the activation of PI3 kinase gamma
Also activates PLC

Question 25

IL-1R signaling also induces

Answer 25

MAP kinase activation and phosphorylation of IRF3 and IRF7, inducers of type I interferon transcription

Question 26

What happens if Lysine 48 is ubiquinated vs lysine 63

Answer 26

Lysine 48 ubiquination targets for destruction

Lysine 63 ubiquination does not target for destruction

Question 27

CD22 is a

Answer 27

B cell specific inhibitor

Question 28

TNF activation can result in

Answer 28

NK-kB and MAP kinase activation or the induction of apoptosis

Question 29

Members of IL-1 or TLR receptor family share

Answer 29

Conserved cytosolic sequence called TIR domain

Question 30

TNF receptor structure

Answer 30

Preformed trimers

Conserved cysteine rich extracellular domains

Question 31

First signal to CD4+ T cell in B cell recognition

Answer 31

MHC II complex engagement with TCR:CD3:CD4 complex is first signal

Question 32

CD21/CD19 co-receptors

Answer 32

Positively regulate B cell activation and serve to lower the Ag threshold for B cell activation

Question 33

JAK-STAT signaling pathway

Answer 33

Ligand binds which activates cytoplasmic receptor associated JAKs
JAKs phosphorylate tyrosine residues along their receptor chains
SH2 domain containing STATs bind to these residues
STATs are phosphorylated by JAK proteins
STAT proteins dimerize and translocate to nucleus

Question 34

Which interaction provides costimulation to the CD4 T cell

Answer 34

CD28:CD86/80 interaction

Question 35

FcyRIIB (CD32) is an important

Answer 35

Attenuator of signaling in activated B cells, DCs and macrophages

Question 36

Most important TNF receptors

Answer 36

TNFRI, TNFRII, CD40, Fas (First apoptosis signal)

Question 37

Phosphorylated CD19 activates

Answer 37

PI3 kinase, which in turn activates Btk and PLCy2

Net result of coreceptor activation is that the response of Ag stimulated B cell is greatly enhanced

Question 38

Role of complements in B cell activation

Answer 38

C3b is degraded into C3d
B cells have C3d receptor called CR2( CD21)
Complex of C3d and Ag binds B cells, with BCR recognizing Ag and CR2 recognize C3d

Question 39

Lyn kinase involvement in BCR signaling

Answer 39

Lyn kinase is bound to CD19
C3d-CR2 binding brings CD19 in proximity to BCR associated kinases
Lyn kinase amplifies BCR signaling by greatly enhancing phosphorylation of ITAMs in Iga and Igb