A Dynamically Assembled Cell Wall Synthesis Machinery Buffers Cell Growth
A dynamically assembled cell wall synthesis machinery buffers cell growth Timothy K. Leea, Carolina Tropinia,b, Jen Hsina, Samantha M. Desmaraisa, Tristan S. Ursella, Enhao Gonga, Zemer Gitaic, Russell D. Mondsa,1,2, and Kerwyn Casey Huanga,b,d,1 aDepartment of Bioengineering and bBiophysics Program, Stanford University, Stanford, CA 94305; cDepartment of Molecular Biology, Princeton University, Princeton, NJ 08544; and dDepartment of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305 Edited by Carol A. Gross, University of California, San Francisco, CA, and approved January 15, 2014 (received for review July 30, 2013) Assembly of protein complexes is a key mechanism for achieving support for the hypothesis that coordination between MreB and spatial and temporal coordination in processes involving many the wall synthesis machinery is achieved through colocalization enzymes. Growth of rod-shaped bacteria is a well-studied example into large, moving, multienzyme complexes (4, 5). However, bio- requiring such coordination; expansion of the cell wall is thought chemical isolation of such a complex has remained elusive (6), to involve coordination of the activity of synthetic enzymes raising the possibility that this picture is incomplete, particularly with the cytoskeleton via a stable complex. Here, we use single- in E. coli, in which dynamic imaging of the PBPs has not yet molecule tracking to demonstrate that the bacterial actin homolog been achieved. MreB and the essential cell wall enzyme PBP2 move on timescales PBP2 is thought to be the major enzyme responsible for co- orders of magnitude apart, with drastically different characteristic valently cross-linking new glycan strands into the cell wall during motions.
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