MHC Class I抗原提示機構におけるTAP依存性ペプチド転送機能の解析 : ペプチドによる至適条件の違いについて

概要

論文の詳細を見る
MHC class I molecules bind to antigenic peptides in the endoplasmic reticulum (ER), and present themselves on the cell surface. MHC class I-bound antigenic peptides are produced by proteasomal degradation of cytosolic or nuclear proteins, followed by their translocation into the ER. The peptide translocation is mediated by transporters associated with antigen processing (TAP1 and TAP2). TAP1 and TAP2 are members of the ATP-binding cassette family of membrane transporters. Since the repertoire of antigenic peptides translocated into the ER largely depends on the efficiency and peptide selectivity of TAP, the functional analysis of TAP is important for characterizing MHC class I-bound antigenic peptides. Using a permiabilized cell system, we analyzed optimal conditions for TAP-dependent translocation of four synthetic model peptides in T1 cells or RMA cells. It was revealed that each peptide had distinct kinetics of translocation and distinct optimal ATP concentration. Furthermore, one of the peptides failed to be translocated by TAP, though it contained high affinity amino acids to TAP in the N-terminus and C-terminus. Our data highlighted the as yet unknown peptide selectivity and ATP concentration-mediated regulatory mechanism of TAP function.
札幌医科大学の論文
1999-06-01