Phosphorylation of the Peptidoglycan Synthase PonA1 Governs the Rate of Polar Elongation in Mycobacteria

PLoS Pathogens

Karen J. Kieser¹  E. Hesper Rego¹  Cara C. Boutte¹  Eric J. Rubin¹  Michael C. Chao¹  Sarah M. Fortune¹  Jemila C. Kester¹  Xavier Meniche²  Christina E. Baer²  Christopher M. Sassetti²  Amy K. Barczak³ 

[1] Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America;Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America;Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America

关键词: Mycobacterium tuberculosis;    Phosphorylation;    Cell walls;    Cross-linking;    Peptidoglycans;    Cell cycle;    cell division;    Cell polarity;    Antibiotics;   

DOI  :  10.1371/journal.ppat.1005010

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Cell growth and division are required for the progression of bacterial infections. Most rod-shaped bacteria grow by inserting new cell wall along their mid-section. However, mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce new cell wall material at their poles. How mycobacteria control this different mode of growth is incompletely understood. Here we find that PonA1, a penicillin binding protein (PBP) capable of transglycosylation and transpeptidation of cell wall peptidoglycan (PG), is a major governor of polar growth in mycobacteria. PonA1 is required for growth of Mycobacterium smegmatis and is critical for M. tuberculosis during infection. In both cases, PonA1’s catalytic activities are both required for normal cell length, though loss of transglycosylase activity has a more pronounced effect than transpeptidation. Mutations that alter the amount or the activity of PonA1 result in abnormal formation of cell poles and changes in cell length. Moreover, altered PonA1 activity results in dramatic differences in antibiotic susceptibility, suggesting that a balance between the two enzymatic activities of PonA1 is critical for survival. We also find that phosphorylation of a cytoplasmic region of PonA1 is required for normal activity. Mutations in a critical phosphorylated residue affect transglycosylase activity and result in abnormal rates of cell elongation. Together, our data indicate that PonA1 is a central determinant of polar growth in mycobacteria, and its governance of cell elongation is required for robust cell fitness during both host-induced and antibiotic stress.

【 授权许可】

CC BY