Jasanoff A, Park S J, Wiley D C
Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9900-4. doi: 10.1073/pnas.92.21.9900.
Invariant chain (Ii) is a trimeric membrane protein which binds and stabilizes major histocompatibility complex class II heterodimers in the endoplasmic reticulum and lysosomal compartments of antigen-presenting cells. In concert with an intracellular class II-like molecule, HLA-DM, Ii seems to facilitate loading of conventional class II molecules with peptides before transport of the class II-peptide complex to the cell surface for recognition by T cells. The interaction of Ii with class II molecules is thought to be mediated in large part through a region of 24 amino acids (the class II-associated Ii peptide, CLIP) which binds as a cleaved moiety in the antigenic peptide-binding groove of class II molecules in HLA-DM-deficient cell lines. Here we use nuclear magnetic resonance techniques to demonstrate that a soluble recombinant Ii ectodomain contains significant disordered regions which probably include CLIP.
恒定链（Ii）是一种三聚体膜蛋白，它在内质网和抗原呈递细胞的溶酶体区室中结合并稳定主要组织相容性复合体II类异二聚体。与细胞内类似II类的分子HLA-DM协同作用，Ii似乎在II类分子 - 肽复合物转运到细胞表面以供T细胞识别之前，促进常规II类分子加载肽段。Ii与II类分子的相互作用被认为在很大程度上是通过一个24个氨基酸的区域（II类相关Ii肽，CLIP）介导的，在缺乏HLA-DM的细胞系中，该区域作为切割部分结合在II类分子的抗原肽结合槽中。在这里，我们使用核磁共振技术证明可溶性重组Ii胞外结构域包含可能包括CLIP的显著无序区域。
