Human Hla Class 2 Histocompatibility Antigen Gamma Chain, CD74 ELI

Plays a critical role in MHC class II antigen processing by stabilizing Peptide-free class II alpha/beta heterodimers in a complex soon after their synthesis and directing transport of the complex from the endoplasmic reticulum to the endosomal/lysosomal system where the antigen processing and binding of antigenic Peptides to MHC class II takes place.

Serves as cell surface receptor for the cytokine MIF.

[Class-II-associated invariant chain Peptide]: Binds to the Peptide-binding site of MHC class II alpha/beta heterodimers forming an alpha-beta-CLIP complex, thereby preventing the loading of antigenic Peptides to the MHC class II complex until its release by HLA-DM in the endosome.

[Isoform p41]: Stabilizes the conformation of mature CTSL by binding to its active site and serving as a chaperone to help maintain a pool of mature enzyme in endocytic compartments and extracellular space of antigen-presenting cells (APCs).

Has antiviral activity by stymieing the endosomal entry of Ebola virus and coronaviruses, including SARS-CoV-2 (PubMed: 32855215).

Disrupts cathepsin-mediated Ebola virus glycoprotein processing, which prevents viral fusion and entry.

This antiviral activity is specific to p41 isoform (PubMed: 32855215).