Mutations in the nucleotide binding pocket of MreB can alter cell curvature and polar morphology in Caulobacter

Natalie A. Dye, Zachary Pincus, Isabelle C. Fisher, Lucy Shapiro, Julie A. Theriot

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

The maintenance of cell shape in Caulobacter crescentus requires the essential gene mreB, which encodes a member of the actin superfamily and the target of the antibiotic, A22. We isolated 35 unique A22-resistant Caulobacter strains with single amino acid substitutions near the nucleotide binding site of MreB. Mutations that alter cell curvature and mislocalize the intermediate filament crescentin cluster on the back surface of MreB's structure. Another subset have variable cell widths, with wide cell bodies and actively growing thin extensions of the cell poles that concentrate fluorescent MreB. We found that the extent to which MreB localization is perturbed is linearly correlated with the development of pointed cell poles and variable cell widths. Further, we find that a mutation to glycine of two conserved aspartic acid residues that are important for nucleotide hydrolysis in other members of the actin superfamily abolishes robust midcell recruitment of MreB but supports a normal rate of growth. These mutant strains provide novel insight into how MreB's protein structure, subcellular localization, and activity contribute to its function in bacterial cell shape.

Original languageEnglish
Pages (from-to)368-394
Number of pages27
JournalMolecular Microbiology
Volume81
Issue number2
DOIs
StatePublished - Jul 2011

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