CD1d degradation in Chlamydia trachomatis-infected epithelial cells is the result of both cellular and chlamydial proteasomal activity

Kei Kawana, Alison J. Quayle, Mercedes Ficarra, Joyce A. Ibana, Li Shen, Yukiko Kawana, Huixia Yang, Luis Marrero, Sujata Yavagal, Sheila J. Greene, You Xun Zhang, Richard B. Pyles, Richard S. Blumberg, Danny J. Schust

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Chlamydia trachomatis is an obligate intracellular pathogen that can persist in the urogenital tract. Mechanisms by which C. trachomatis evades clearance by host innate immune responses are poorly described. CD1d is MHC-like, is expressed by epithelial cells, and can signal innate immune responses by NK and NKT cells. Here we demonstrate that C. trachomatis infection down-regulates surface-expressed CD1d in human penile urethral epithelial cells through proteasomal degradation. A chlamydial proteasome-like activity factor (CPAF) interacts with the CD1d heavy chain, and CPAF-associated CD1d heavy chain is then ubiquitinated and directed along two distinct proteolytic pathways. The degradation of immature glycosylated CD1d was blocked by the proteasome inhibitor lactacystin but not by MG132, indicating that degradation was not via the conventional proteasome. In contrast, the degradation of non-glycosylated CD1d was blocked by lactacystin and MG132, consistent with conventional cellular cytosolic degradation of N-linked glycoproteins. Immunofluorescent microscopy confirmed the interruption of CD1d trafficking to the cell surface, and the dislocation of CD1d heavy chains into both the cellular cytosol and the chlamydial inclusion along with cytosolic CPAF. C. trachomatis targeted CD1d toward two distinct proteolytic pathways. Decreased CD1d surface expression may help C. trachomatis evade detection by innate immune cells and may promote C. trachomatis persistence.

Original languageEnglish (US)
Pages (from-to)7368-7375
Number of pages8
JournalJournal of Biological Chemistry
Volume282
Issue number10
DOIs
StatePublished - Mar 2 2007

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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