Role of Acetyl-Phosphate in Activation of the Rrp2-RpoN-RpoS Pathway in Borrelia burgdorferi

PLoS Pathogens

Ming He¹  Frank Gheradini¹  Steven J. Norris²  Tao Lin²  Melissa J. Caimano³  Justin D. Radolf³  Alan J. Wolfe⁴  Haijun Xu⁵  X. Frank Yang⁶ 

[1] Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America;Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America;Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America;Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America;Institute of Insect Science, Zhejiang University, Hangzhou, China;National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratories, Hamilton, Montana, United States of America

关键词: Borrelia burgdorferi;    Phosphorylation;    Hyperexpression techniques;    Spirochetes;    Histidine;    Polymerase chain reaction;    Regulator genes;    Vector cloning;   

DOI  :  10.1371/journal.ppat.1001104

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Borrelia burgdorferi, the Lyme disease spirochete, dramatically alters its transcriptome and proteome as it cycles between the arthropod vector and mammalian host. During this enzootic cycle, a novel regulatory network, the Rrp2-RpoN-RpoS pathway (also known as the σ54–σS sigma factor cascade), plays a central role in modulating the differential expression of more than 10% of all B. burgdorferi genes, including the major virulence genes ospA and ospC. However, the mechanism(s) by which the upstream activator and response regulator Rrp2 is activated remains unclear. Here, we show that none of the histidine kinases present in the B. burgdorferi genome are required for the activation of Rrp2. Instead, we present biochemical and genetic evidence that supports the hypothesis that activation of the Rrp2-RpoN-RpoS pathway occurs via the small, high-energy, phosphoryl-donor acetyl phosphate (acetyl∼P), the intermediate of the Ack-Pta (acetate kinase-phosphate acetyltransferase) pathway that converts acetate to acetyl-CoA. Supplementation of the growth medium with acetate induced activation of the Rrp2-RpoN-RpoS pathway in a dose-dependent manner. Conversely, the overexpression of Pta virtually abolished acetate-induced activation of this pathway, suggesting that acetate works through acetyl∼P. Overexpression of Pta also greatly inhibited temperature and cell density-induced activation of RpoS and OspC, suggesting that these environmental cues affect the Rrp2-RpoN-RpoS pathway by influencing acetyl∼P. Finally, overexpression of Pta partially reduced infectivity of B. burgdorferi in mice. Taken together, these findings suggest that acetyl∼P is one of the key activating molecule for the activation of the Rrp2-RpoN-RpoS pathway and support the emerging concept that acetyl∼P can serve as a global signal in bacterial pathogenesis.

【 授权许可】

CC BY