Vocabulary and Objectives Week 7 Flashcards Preview

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Flashcards in Vocabulary and Objectives Week 7 Deck (22):
1

PA28

binds to either end of inducible proteosome; Opens up the ends and increases rate at which peptides are released; induced by IFN-g

2

Proteosome

large protease complex that degrades cytosolic proteins

3

Constitutive Proteosome

Always on; has alpha and beta subunits

4

Immunoproteasome

Induced by IFN-g; LMP2, MECL-1, LMP7

5

TAP

binds peptides from cytosol and transports them to the ER lumen to bind to Class I MHC

6

ERAAP

Endoplasmic reticulum aminopeptidase associated with antigen processing; responsible for further processing of peptides so they can better fit into MHC I

7

Rule 1

endogenous antigens are processed and presented in the class I pathway to CD8 T cells, endogenous antigens are found inside the cell

8

Exception to Rule 1

cross presentation allows specialized DC to endocytose virally infected cells and present via class I to naïve CD8 cells; DC can take up pieces of virally infected cells in the endosome that then gets shuttled to the cytosolic compartment to be chopped up via the proteosome

9

How do proteins from phagosome get into cytosol?

Phagosome to cytosol; Retro-translocation through Sec61-Endosome to ER; Fusion of ER and phagosome

10

Calnexin

Binds to MHC I until B2m can bind

11

What three proteins bind to MHCI and stabilize it in the ER?

Calreticulin, Erp57 and calnexin

12

Tapasin

Binds to TAP and aids in TAP presenting peptides to MHC I

13

Antigen processing

refers to the generation of peptides from an intact antigen that involves modification of native protein

14

Antigen presentation

refers to the display of the peptide at the cell surface by MHC molecules to T cells

15

CLIP

Class II Invariant Chain Peptide; sits in the peptide binding cleft of MHC II; stabilizes MHC II and keeps peptides from binding

16

HLA-DM

acts as a peptide exchanger, facilitating the removal of CLIP and the addition of other peptides to class II MHC molecules

17

Autophagy

enzymatic digestion of cytoplasmic contents

18

Invariant Chain

Blocks premature binding of Class II MHC; promotes folding and assembly of class II MHC molecules and directs newly formed class II MHC molecules to the late endosomes and lysosomes; degraded by cathepsins

19

Cathepsins

proteases in endosomal compartments, for class II,

20

Evasins

can degrade class I or
bind to TAP and inhibit peptide loading

21

MIIC endosomal Compartment

contains the enzymes that degrade protein antigens, class II MHC molecules, and two molecules involved in peptide loading of class II MHC molecules, the invariant chain and HLA-DM

22

Where is the Class II MHC molecule generated?

Class II MHC molecules are synthesized in the ER and transported to endosomes with an associated protein, the invariant chain, which occupies the peptide-binding clefts of the newly synthesized class II MHC molecules

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