MHC class II region encoding proteins related to the muKidrug resistance family of transmembrane transporters

摘要: THE T-cell immune response is directed against antigenic peptide fragments generated in intracellular compartments, the cytosol or endocytic system1. Peptides derived from cytosolic proteins, usually of biosynthetic origin, are presented efficiently to receptors by major histocompatibility complex (MHC) class I molecules2–4, with which they assemble, probably endoplas-mic reticulum (ER)5. In absence recognizable N-terminal signal sequences, such peptides must be translocated across ER membrane a novel mechanism. Genes apparently involved normal assembly and transport molecules may themselves encoded MHC6–8. Here we show that one these, rat cim gene6, maps highly polymorphic part MHC II region encoding two members family transmembrane transporters related multidrug resistance9,10. Other this transporter proteins known capable transporting proteins11,12 peptides13 membranes independently classical secretory pathway. Such credible candidates for pumps move into ER14,15.