Fortin Jean-Simon, Cloutier Maryse, Thibodeau Jacques
Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal , Montréal, QC , Canada.
Front Immunol. 2013 Dec 13;4:443. doi: 10.3389/fimmu.2013.00443.
The peptide repertoire (peptidome) associated with MHC class II molecules (MHCIIs) is influenced by the polymorphic nature of the peptide binding groove but also by cell-intrinsic factors. The invariant chain (Ii) chaperones MHCIIs, affecting their folding and trafficking. Recent discoveries relating to Ii functions have provided insights as to how it edits the MHCII peptidome. In humans, the Ii gene encodes four different isoforms for which structure-function analyses have highlighted common properties but also some non-redundant roles. Another layer of complexity arises from the fact that Ii heterotrimerizes, a characteristic that has the potential to affect the maturation of associated MHCIIs in many different ways, depending on the isoform combinations. Here, we emphasize the peptide editing properties of Ii and discuss the impact of the various isoforms on the MHCII peptidome.
与II类主要组织相容性复合体（MHCII）相关的肽库（肽组）不仅受肽结合槽多态性的影响，还受细胞内在因素的影响。恒定链（Ii）作为伴侣蛋白协助MHCII，影响其折叠和运输。最近关于Ii功能的发现为其如何编辑MHCII肽组提供了见解。在人类中，Ii基因编码四种不同的异构体，对其结构功能分析突出了共同特性，但也有一些非冗余作用。另一层复杂性源于Ii形成异源三聚体这一事实，根据异构体组合的不同，这一特性有可能以多种不同方式影响相关MHCII的成熟。在此，我们强调Ii的肽编辑特性，并讨论各种异构体对MHCII肽组的影响。
