Cathepsin E: A Novel Target for Regulation by Class II Transactivator

Christina S.K. Yee, Yongxue Yao, Ping Li, Michael J. Klemsz, Janice S. Blum, Cheong Hee Chang

Research output: Contribution to journalArticle

53 Scopus citations


The aspartic proteinase cathepsin E (CatE) has been implicated in Ag processing. In this study we report that CatE expression is negatively regulated by the MHC class II transactivator (CIITA). CIITA-deficient murine and human B cells expressed greater CatE than wild-type B cells, whereas overexpression of CIITA in a human gastric carcinoma cell line, AGS, resulted in decreased CatE mRNA and protein. AGS cells expressing CIITA also exhibited decreased processing of OVA Ag. Inhibition of CatE expression is specific to the type III CIITA isoform and maps to the acidic and proline/serine/threonine-rich (PST) protein domains of CIITA. We found that CatE expression is inducible by PU.1 and p300, and that this induction can be reversed by CIITA. These findings demonstrate a novel phenomenon: regulation of CatE Ag processing by CIITA in an isoform-dependent manner.

Original languageEnglish (US)
Pages (from-to)5528-5534
Number of pages7
JournalJournal of Immunology
Issue number9
StatePublished - May 1 2004

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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