Predicted to enable oxidoreductase activity, acting on a sulfur group of donors. Involved in antigen processing and presentation of exogenous peptide antigen via MHC class I. Acts upstream of or within antigen processing and presentation of exogenous peptide antigen via MHC class II; negative regulation of fibroblast proliferation; and protein stabilization. Located in lysosome. Is expressed in alimentary system; liver; and orbito-sphenoid. Orthologous to human IFI30 (IFI30 lysosomal thiol reductase). [provided by Alliance of Genome Resources, Apr 2022]