CTSE encodes a member of the A1 family of peptidases. Alternative splicing of CTSE results in multiple transcript variants. At least one of these variants encodes a preproprotein that is proteolytically processed to generate the mature enzyme. This enzyme (cathepsin E, an aspartic endopeptidase, may be involved in antigen processing and the maturation of secretory proteins. Elevated expression of CTSE has been observed in neurodegeneration.