Spies T, Cerundolo V, Colonna M, Cresswell P, Townsend A, DeMars R
Division of Tumor Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
Nature. 1992 Feb 13;355(6361):644-6. doi: 10.1038/355644a0.
Major histocompatibility complex (MHC) class I molecules present peptides derived from the endogenous protein pool to cytotoxic T lymphocytes, which can thus recognize intracellular antigen. This pathway may depend on a transporter (PSF1) to mediate entry of the cytosolic peptides into a pre-Golgi compartment where they bind to class I heavy chains and promote their stable assembly with beta 2-microglobulin. There is, however, only indirect support for this function of PSF1. Here we show that PSF1 is necessary for the efficient assembly of class I molecules and enables them to present a peptide epitope derived from endogenously synthesized viral antigen. Immunochemical and genetic data demonstrate that the PSF1 polypeptide is associated with a complementary transporter chain, which is polymorphic and is encoded by the PSF2 gene, which is closely linked to PSF1.
