Long helical filaments are not seen encircling cells in electron cryotomograms of rod-shaped bacteria

Journal Article · Fri Apr 22 00:00:00 EDT 2011 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/J.BBRC.2011.03.062· OSTI ID:22204889

Swulius, Matthew T.; Chen, Songye; Jane Ding, H. ^[1]; Li, Zhuo ^[2]; Briegel, Ariane ^[1]; Pilhofer, Martin ^[1]; Tocheva, Elitza I. ^[1]; Lybarger, Suzanne R.; Johnson, Tanya L.; Sandkvist, Maria ^[3]

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1. Division of Biology, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States)
2. EM Core Facility, City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 (United States)
3. Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109 (United States)

Highlights: {yields} No long helical filaments are seen near or along rod-shaped bacterial inner membranes by electron cryo-tomography. {yields} Electron cryo-tomography has the resolution to detect single filaments in vivo. -- Abstract: How rod-shaped bacteria form and maintain their shape is an important question in bacterial cell biology. Results from fluorescent light microscopy have led many to believe that the actin homolog MreB and a number of other proteins form long helical filaments along the inner membrane of the cell. Here we show using electron cryotomography of six different rod-shaped bacterial species, at macromolecular resolution, that no long (>80 nm) helical filaments exist near or along either surface of the inner membrane. We also use correlated cryo-fluorescent light microscopy (cryo-fLM) and electron cryo-tomography (ECT) to identify cytoplasmic bundles of MreB, showing that MreB filaments are detectable by ECT. In light of these results, the structure and function of MreB must be reconsidered: instead of acting as a large, rigid scaffold that localizes cell-wall synthetic machinery, moving MreB complexes may apply tension to growing peptidoglycan strands to ensure their orderly, linear insertion.

• OSTI ID: 22204889
• Journal Information: Biochemical and Biophysical Research Communications, Vol. 407, Issue 4; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ACTIN
BACTERIA
BIOLOGY
FLUORESCENCE
IN VIVO
MICROSCOPY
TOMOGRAPHY