Modulation of the antigen transport machinery TAP by friends and enemies.
The transporter associated with antigen processing (TAP) is a key factor of the major histocompatibility complex (MHC) class I antigen presentation pathway. This ABC transporter translocates peptides derived mainly from proteasomal degradation from the cytosol into the ER lumen for loading onto MHC class I molecules. Manifold mechanisms have evolved to regulate TAP activity. During infection, TAP expression is upregulated by interferon-gamma. Furthermore, the assembly and stability of the transport complex is promoted by various auxiliary factors. However, tumors and viruses have developed sophisticated strategies to escape the immune surveillance by suppressing TAP function. The activity of TAP can be impaired on the transcriptional or translational level, by enhanced degradation or by inhibition of peptide translocation. In this review, we briefly summarize existing data concerning the regulation of the TAP complex.
Abele
Rupert
R
Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Marie-Curie-Str. 9, D-60439 Frankfurt/M., Germany.
Tampé
Robert
R
D018528:ATP-Binding Cassette Transporters; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000502:physiology*; D006801:Humans; D008285:Major Histocompatibility Complex / Q000502:physiology; D014780:Viruses / Q000276:immunology
D018528:ATP-Binding Cassette Transporters; D015395:Histocompatibility Antigens Class I; C477327:transporter associated with antigen processing (TAP)