Microtubules are dynamic polymers, which grow and shrink by addition and removal of tubulin dimers at their extremities. Within the microtubule shaft, dimers adopt a densely packed and highly ordered crystal-like lattice structure, which is generally not considered to be dynamic. Here we report that thermal forces are sufficient to remodel the microtubule shaft, despite its apparent stability. Our combined experimental data and numerical simulations on lattice dynamics and structure suggest that dimers can spontaneously leave and be incorporated into the lattice at structural defects. We propose a model mechanism, where the lattice dynamics is initiated via a passive breathing mechanism at dislocations, which are frequent in rapidly growing microtubules. These results show that we may need to extend the concept of dissipative dynamics, previously established for microtubule extremities, to the entire shaft, instead of considering it as a passive material.
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http://dx.doi.org/10.1038/s41567-019-0542-4 | DOI Listing |
Curr Biol
October 2024
Nerve Regeneration Group, IBMC-Instituto de Biologia Molecular e Celular and i3S - Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal. Electronic address:
Neurons have a unique polarized nature that must adapt to environmental changes throughout their lifespan. During embryonic development, axon elongation is led by the growth cone, culminating in the formation of a presynaptic terminal. After synapses are formed, axons elongate in a growth cone-independent manner to accompany body growth while maintaining their ultrastructure and function.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
June 2024
Department of Biochemistry, University of Geneva, Geneva, Switzerland.
bioRxiv
May 2024
Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.
Axonal outgrowth, cell crawling, and cytokinesis utilize actomyosin, microtubule-based motors, cytoskeletal dynamics, and substrate adhesions to produce traction forces and bulk cellular motion. While it has long been appreciated that growth cones resemble crawling cells and that the mechanisms that drive cytokinesis help power cell crawling, they are typically viewed as unique processes. To better understand the relationship between these modes of motility, here, we developed a unified active fluid model of cytokinesis, amoeboid migration, mesenchymal migration, neuronal migration, and axonal outgrowth in terms of cytoskeletal flow, adhesions, viscosity, and force generation.
View Article and Find Full Text PDFCurr Biol
June 2024
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA. Electronic address:
The Mps1 and Aurora B kinases regulate and monitor kinetochore attachment to spindle microtubules during cell division, ultimately ensuring accurate chromosome segregation. In yeast, the critical spindle attachment components are the Ndc80 and Dam1 complexes (Ndc80c and DASH/Dam1c, respectively). Ndc80c is a 600-Å-long heterotetramer that binds microtubules through a globular "head" at one end and centromere-proximal kinetochore components through a globular knob at the other end.
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