Dependence of Peptide Binding by MHC Class I Molecules on Their Interaction with TAP

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Science  06 Oct 1995:
Vol. 270, Issue 5233, pp. 105-108
DOI: 10.1126/science.270.5233.105


Major histocompatibility complex (MHC) class I molecules bind peptides that are delivered from the cytosol into the endoplasmic reticulum by the MHC-encoded transporter associated with antigen processing (TAP). Peptide capture by immature heterodimers of class I heavy chains and β2-microglobulin may be facilitated by their physical association with TAP. A genetic defect in a human mutant cell line causes the complete failure of diverse class I heterodimers to associate with TAP. This deficiency impairs the ability of the class I heterodimers to efficiently capture peptides and results from loss of function of an unidentified gene or genes linked to the MHC.