Microtubules become more dynamic but not shorter during preprophase band formation: a possible "search-and-capture" mechanism for microtubule translocation

Cell Motil Cytoskeleton. 2004 Apr;57(4):246-58. doi: 10.1002/cm.10169.

Abstract

The dynamic behavior of the microtubule cytoskeleton plays a crucial role in cellular organization, but the physical mechanisms underlying microtubule (re)organization in plant cells are poorly understood. We investigated microtubule dynamics in tobacco BY-2 suspension cells during interphase and during the formation of the preprophase band (PPB), the cytoskeletal structure that defines the site of cytokinesis. Here we show that after 2 h of microtubule accumulation in the PPB and concurrent disappearance elsewhere in the cortex, the PPB is completed and starts to breakdown exponentially already 20 min before the onset of prometaphase. During formation of the PPB, the dynamic instability, i.e., the stochastic alternating between growing and shrinking phases, of the cortical microtubules outside the PPB increases significantly, but the microtubules do not become shorter. Based on this, as well as on the cross-linking of microtubules in the PPB and the lack of evidence for motor involvement, we propose a "search-and-capture" mechanism for PPB formation, in which the regulation of dynamic instability causes the cortical microtubules to become more dynamic and possibly longer, while the microtubule cross-linking activity of the developing PPB preferentially stabilizes these "searching" microtubules. Thus, microtubules gradually disappear from the cortex outside the PPB and aggregate to the forming PPB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Cells, Cultured
  • G2 Phase / physiology
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Interphase / physiology
  • Kinetics
  • Microscopy, Fluorescence
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism
  • Microtubules / metabolism*
  • Models, Biological*
  • Molecular Motor Proteins / metabolism
  • Prophase / physiology*
  • Protein Transport / physiology
  • Tobacco / cytology
  • Tobacco / genetics
  • Tobacco / physiology
  • Transformation, Genetic
  • Tubulin / metabolism

Substances

  • MAP4
  • Microtubule-Associated Proteins
  • Molecular Motor Proteins
  • Tubulin
  • Green Fluorescent Proteins