This Article Full Text Full Text (PDF) Supplement All Versions of this Article: biophysj.105.076893v1 92/3/1046    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lagomarsino, M. C. Articles by Dogterom, M. Search for Related Content PubMed PubMed Citation Articles by Lagomarsino, M. C. Articles by Dogterom, M.

Microtubule Organization in Three-Dimensional Confined Geometries: Evaluating the Role of Elasticity Through a Combined In Vitro and Modeling Approach

Marco Cosentino Lagomarsino ^*, Catalin Tanase ^*, Jan W. Vos ^* , Anne Mie C. Emons ^* , Bela M. Mulder ^*  and Marileen Dogterom ^*

^* FOM Institute for Atomic and Molecular Physics (AMOLF), 1098 SJ Amsterdam, The Netherlands; and Wageningen University, Laboratory of Plant Cell Biology, 6703 BD Wageningen, The Netherlands

Correspondence: Address reprint requests to Marileen Dogterom, E-mail: dogterom{at}amolf.nl.

Microtubules or microtubule bundles in cells often grow longer than the size of the cell, which causes their shape and organization to adapt to constraints imposed by the cell geometry. We test the reciprocal role of elasticity and confinement in the organization of growing microtubules in a confining box-like geometry, in the absence of other (active) microtubule organizing processes. This is inspired, for example, by the cortical microtubule array of elongating plant cells, where microtubules are typically organized in an aligned array transverse to the cell elongation axis. The method we adopt is a combination of analytical calculations, in which the polymers are modeled as inextensible filaments with bending elasticity confined to a two-dimensional surface that defines the limits of a three-dimensional space, and in vitro experiments, in which microtubules are polymerized from nucleation seeds in microfabricated chambers. We show that these features are sufficient to organize the polymers in aligned, coiling configurations as for example observed in plant cells. Though elasticity can account for the regularity of these arrays, it cannot account for a transverse orientation of microtubules to the cell's long axis. We therefore conclude that an additional active, force-generating process is necessary to create a coiling configuration perpendicular to the long axis of the cell.