(
A) Crystal structure and cartoon representation of MHC-I (red: heavy chain, orange: β2m, yellow: peptide)/TCR (green) (PDB 5C07
3) on CD8
+ T cells, MHC-I/CD8 co-receptor (cyan and magenta) (PDB 3DMM
4 and PDB 3QZW
5), or MHC-I/KIR3DL1 (blue) on natural killer (NK) cells (PDB 5B38
6). (
B) Cryo-EM structure of MHC-I in the PLC (yellow: calreticulin, blue: tapasin, purple: ERp57) (PDB 6ENY
7 adapted from data freely accessible at:
https://www.rcsb.org/structure/6ENY) or with TAPBPR (cyan) (PDB 5WER
8) in the peptide-deficient form. Arrows highlight interactions between tapasin and MHC-I, calreticulin and the MHC-I glycan, calreticulin and tapasin, calreticulin and ERp57, and tapasin and Erp57. β2m, beta2-microglobulin; KIR, killer cell immunoglobulin-like receptor; PLC, peptide loading complex; TAPBPR, transporter associated with antigen presentation-binding protein related; TCR, T-cell receptor.