Localization and characterization of a putative cysteine desulfurase in Chlamydia psittaci |
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Authors: | Yating Wen Yanbo Chen Li Li Man Xu Yuan Tan Yumeng Li Chuan Wang Qian Chen Xingxing Kuang Yimou Wu |
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Institution: | 1. Institute of Pathogenic Biology, Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China;2. Department of Clinical Laboratory, Jiangmen Wuyi Traditional Chinese Medicine Hospital, Jiangmen, China;3. Toxicology Laboratory, Hunan Provincial Center for Disease Control and Prevention, Changsha, China |
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Abstract: | Chlamydia psittaci is an obligate intracellular pathogen with a biphasic developmental life cycle. It is auxotrophic for a variety of essential metabolites and obtains amino acids from eukaryotic host cells. Chlamydia can develop inside host cells within chlamydial inclusions. A pathway secreting proteins from inclusions into the host cellular cytoplasm is the type III secretion system (T3SS). The T3SS is universal among several Gram-negative bacteria. Here, we show that CPSIT_0959 of C. psittaci is expressed midcycle and secreted into the infected cellular cytoplasm via the T3SS. Recombinant CPSIT_0959 possesses cysteine desulfurase and PLP-binding activity, which removes sulfur from cysteine to produce alanine, and helps chlamydial replication. Our study shows that CPSIT_0959 improve the infectivity of offspring elementary bodies and seems to promote the replication by its product. This phenomenon has inhibited by the PLP-dependent enzymes inhibitor. Moreover, CPSIT_0959 increased expression of Bim and tBid, and decreased the mitochondrial membrane potential of host mitochondria to induce apoptosis in the latecycle for release of offspring. These results demonstrate that CPSIT_0959 has cysteine desulfurase and PLP-binding activity and is likely to contribute to apoptosis of the infected cells via a mitochondria-mediated pathway to improve the infectivity of progeny. |
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Keywords: | cellular localization Chlamydia psittaci cysteine desulfurase mitochondria-mediated pathway T3SS |
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