Ingham-6: MHC I Flashcards
What does MHC stand for?
Major Histocompatibility Complex
Where can MHC I receptors be found?
Surface of all nucleated cells
What cytokine can induce higher expressions of MHC I?
IFN-gamma
What type peptides does MHC I usu. present?
endogenous
What are the 2 chain types that make up MHC I
- alpha chains
- beta-2-microglobulin
How big of a peptide does MHC I peptide binding groove bind?
8-10 aa
What makes up the MHC I peptide binding domain?
alpha 1 and 2 domains (2 alpha helices and 1 beta sheet)
Why is there a limit on the size of peptide bound on the groove?
ends of MHC I groove is closed off
Where can MHC II receptors be found?
surface of pAPCs
What type of peptides do MHC II usu. present?
exogenous
What comprises the MHC II receptor?
alpha and beta chain
What makes up the binding cleft of MHC II?
alpha and beta chain (alpha 1 and beta 1 domain)
How big are the peptides that bind to the MHC II groove?
13-18 aa
What allows MHC II to bind bigger peptides?
the ends of its groove are open
What are the 2 main differences that distinguish MHC I and MHC II?
size and source of peptides they bind
Where is the Human MHC region located in DNA?
Chromosome 6
What are the 3 classical MHC I genes?
HLA-A, B, C
What are the 3 classical MHC II genes?
HLA-DP, DQ, DR
Is HLA-G classical or non-classical MHC?
non-classical
Function of HLA-G
prevents rejection of fetus by mother
Function of HLA-DM in MHC II
- nonclassical
- involved in peptide loading onto MHC II
3 important characteristics of classical MHC genes
- polygenic
- polymorphic
- co-dominant
Where are the polymorphisms located in MHC I?
alpha 1 and 2 domains –> the peptide binding groove
Anchor residues
similar aa types at specific positions of peptides
Characteristics of anchor residues of peptides for MHC I (x2)
- usu. hydrophobic
- usu. located at C-terminal
Characteristics of anchor residues of peptides for MHC II (x2)
- usu. at the centre of peptide
- more variable
