Identification of a chlamydial protease-like activity factor responsible for the degradation of host transcription factors.
Microbial pathogens have been selected for the capacity to evade or manipulate host responses in order to survive after infection. Chlamydia, an obligate intracellular pathogen and the causative agent for many human diseases, can escape T lymphocyte immune recognition by degrading host transcription factors required for major histocompatibility complex (MHC) antigen expression. We have now identified a chlamydial protease- or proteasome-like activity factor (CPAF) that is secreted into the host cell cytosol and that is both necessary and sufficient for the degradation of host transcription factors RFX5 and upstream stimulation factor 1 (USF-1). The CPAF gene is highly conserved among chlamydial strains, but has no significant overall homology with other known genes. Thus, CPAF represents a unique secreted protein produced by an obligate intracellular bacterial pathogen to interfere with effective host adaptive immunity.
Zhong
G
G
Department of Microbiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA. zhong@uthscsa.edu
Fan
P
P
Ji
H
H
Dong
F
F
Huang
Y
Y
D002474:Cell-Free System; D002692:Chlamydia trachomatis / Q000201:enzymology / Q000472:pathogenicity / Q000502:physiology*; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D010450:Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008285:Major Histocompatibility Complex; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000378:metabolism*; D051720:Upstream Stimulatory Factors
D004268:DNA-Binding Proteins; C093524:RFX5 protein, human; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors; D010450:Endopeptidases; C425923:CPA factor