MHC 3 Flashcards
Where is MHCII assembled?
ER
As well as the alpha and beta subunits, what else does the MHCII molecule assemble with?
The invariant chain
Where does a part of the invariant chain sit in MHCII?
Within the peptide binding groove
Why does the MHCII not bind to peptides in the ER?
The peptide binding groove is occluded by the invariant chain
What happens to the invariant chain once the MHCII has left the ER in a vesicle?
It is degraded
What is left in the peptide binding groove of the MHCII after the invariant chain ha been degreaded?
A short peptide called CLIP
What happens once the MHCII reaches the phagolysosome?
HLADM facilitates the removal of CLIP
How does HLADM facilitate the removal of CLIP?
It resembles the MHC molecule
What happens once CLIP is removed from the peptide binding groove by HLADM?
Peptides in the phagolysosome can now bind to the MHCII
What happens after peptides from the phagolysosome bind to the MHCII?
MHCII moves to the cell surface and presents at the cell surface
What are the most polymorphic MHC isotypes?
HLAA, HLAB, HLAC
What chromosome contains the MHC/HLA genes?
Chromosome 6
Which region of the chromosome are HLAA, HLABB, and HLABC coded?
Class I region
How do you expres 6 diff variants of MHCI?
3 haplotypes of A B and C from your mother, and 3 haplotypes of each from your father
What other things are encoded in the part of chromosome 6 that is responsible for MHC molecules?
Bits of antibodies, TAP transporter
What are diff types of MHC molecules called?
Allotypes
Where is the most variability in MHC molecules?
Peptide binding grooves
Advantage of being polymorphic–> 6 diff variants of MHC?
Gives you more coverage of peptides–> can present a wider range of peptides
