Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells

Andrew D. Bicek, Erkan Tüzel, Aleksey Demtchouk, Maruti Uppalapati, William O. Hancock, Daniel M. Kroll, David J. Odde

Research output: Contribution to journalArticle

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Abstract

Microtubules (MTs) have been proposed to act mechanically as compressive struts that resist both actomyosin contractile forces and their own polymerization forces to mechanically stabilize cell shape. To identify the origin of MT bending, we directly observed MT bending and F-actin transport dynamics in the periphery of LLC-PK1 epithelial cells. We found that F-actin is nearly stationary in these cells even as MTs are deformed, demonstrating that MT bending is not driven by actomyosin contractility. Furthermore, the inhibition of myosin II activity through the use of blebbistatin results in microtubules that are still dynamically bending. In addition, as determined by fluorescent speckle microscopy, MT polymerization rarely results, if ever, in bending. We suppressed dynamic instability using nocodazole, and we observed no qualitative change in the MT bending dynamics. Bending most often results from anterograde transport of proximal portions of the MT toward a nearly stationary distal tip. Interestingly, we found that in an in vitro kinesin-MT gliding assay, MTs buckle in a similar manner. To make quantitative comparisons, we measured curvature distributions of observed MTs and found that the in vivo and in vitro curvature distributions agree quantitatively. In addition, the measured MT curvature distribution is not Gaussian, as expected for a thermally driven semiflexible polymer, indicating that thermal forces play a minor role in MT bending. We conclude that many of the known mechanisms of MT deformation, such as polymerization and acto-myosin contractility, play an inconsequential role in mediating MT bending in LLC-PK1 cells and that MT-based molecular motors likely generate most of the strain energy stored in the MT lattice. The results argue against models in which MTs play a major mechanical role in LLC-PK1 cells and instead favor a model in which mechanical forces control the spatial distribution of the MT array.

Original languageEnglish (US)
Pages (from-to)2943-2953
Number of pages11
JournalMolecular biology of the cell
Volume20
Issue number12
DOIs
StatePublished - Jun 15 2009

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LLC-PK1 Cells
Microtubules
Epithelial Cells
Polymerization
Actomyosin
pioglitazone
Actins

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Cite this

Bicek, A. D., Tüzel, E., Demtchouk, A., Uppalapati, M., Hancock, W. O., Kroll, D. M., & Odde, D. J. (2009). Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells. Molecular biology of the cell, 20(12), 2943-2953. https://doi.org/10.1091/mbc.E08-09-0909
Bicek, Andrew D. ; Tüzel, Erkan ; Demtchouk, Aleksey ; Uppalapati, Maruti ; Hancock, William O. ; Kroll, Daniel M. ; Odde, David J. / Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells. In: Molecular biology of the cell. 2009 ; Vol. 20, No. 12. pp. 2943-2953.
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Bicek, AD, Tüzel, E, Demtchouk, A, Uppalapati, M, Hancock, WO, Kroll, DM & Odde, DJ 2009, 'Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells', Molecular biology of the cell, vol. 20, no. 12, pp. 2943-2953. https://doi.org/10.1091/mbc.E08-09-0909

Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells. / Bicek, Andrew D.; Tüzel, Erkan; Demtchouk, Aleksey; Uppalapati, Maruti; Hancock, William O.; Kroll, Daniel M.; Odde, David J.

In: Molecular biology of the cell, Vol. 20, No. 12, 15.06.2009, p. 2943-2953.

Research output: Contribution to journalArticle

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T1 - Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells

AU - Bicek, Andrew D.

AU - Tüzel, Erkan

AU - Demtchouk, Aleksey

AU - Uppalapati, Maruti

AU - Hancock, William O.

AU - Kroll, Daniel M.

AU - Odde, David J.

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