MHC class I assembly: out and about

Trends Immunol. 2008 Sep;29(9):436-43. doi: 10.1016/


The assembly of major histocompatibility complex (MHC) class I molecules with peptides is orchestrated by several assembly factors including the transporter associated with antigen processing (TAP) and tapasin, the endoplasmic reticulum (ER) oxido-reductases ERp57 and protein disulfide isomerase (PDI), the lectin chaperones calnexin and calreticulin, and the ER aminopeptidase (ERAAP). Typically, MHC class I molecules present endogenous antigens to cytotoxic T lymphocytes (CTLs). However, the initiation of CD8(+) T-cell responses against many pathogens and tumors also requires the presentation of exogenous antigens by MHC class I molecules. We discuss recent developments relating to interactions and mechanisms of function of the various assembly factors and pathways by which exogenous antigens access MHC class I molecules.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • ATP-Binding Cassette Transporters / immunology
  • ATP-Binding Cassette Transporters / metabolism
  • Animals
  • Antigen Presentation / immunology*
  • Cross-Priming / immunology
  • Histocompatibility Antigens Class I / immunology*
  • Histocompatibility Antigens Class I / metabolism
  • Humans
  • Leucyl Aminopeptidase / immunology
  • Leucyl Aminopeptidase / metabolism
  • Membrane Transport Proteins / immunology
  • Membrane Transport Proteins / metabolism
  • Models, Immunological
  • Peptides / immunology
  • Peptides / metabolism


  • ATP-Binding Cassette Transporters
  • Histocompatibility Antigens Class I
  • Membrane Transport Proteins
  • Peptides
  • tapasin
  • transporter associated with antigen processing (TAP)
  • Leucyl Aminopeptidase
  • puromycin-insensitive leucyl-specific aminopeptidase