Spindle-F-Actin, Molecular Gearshifts, and Cytoplasmic Softening

Must Read

Spindle-F-Actin Interactions in Mitotic Spindles in an Intact Vertebrate Epithelium

Kita et al. | Molecular Biology of the Cell A compelling subject for striking microscopy images, microtubules have long been considered the major mechanical component of the mitotic spindle. But a long-standing question has been whether a second cytoskeletal system lurks beneath the surface. In this study, the Bement lab develops improved methods for preserving F-actin in embryonic epithelia and successfully visualizes F-actin associated with the mitotic spindle. The authors demonstrate that, like spindle microtubules, multiple populations of spindle-F-actin exist and reorganize as a function of the cell cycle. By providing some of the first evidence that F-actin is a component of the mitotic spindle in animal cells, this study challenges the view that F-actin is restricted to the cell periphery during cell division.

Methods

In Vitro BioID: Mapping the CENP-A Microenvironment with High Temporal and Spatial Resolution

Enhancements to a proximity-based labeling approach allow mapping of cell-cycle-dependent structural proteins.
Remnant et al.  |  Molecular Biology of the Cell
 

Reviews and Perspectives

Tools and Resources

Journal Club Picks

• Actin and myosin self-organize into active liquid droplets reminiscent of the mitotic spindle.
  Weirich et al. |  Gardel Lab |  Proceedings of the National Academy of Sciences
• The microtubule seam is as strong as other regions of the lattice.
  Szatkowski et al. |  Dima Lab |  The Journal of Physical Chemistry
• A dynein mutant uncouples ATPase activity and directed movement.
  Niekamp et al. |  Bhabha Lab |  The EMBO Journal
• The kinesin-1 neck linker acts as a molecular gearshift, toggling between force and speed.
  Budaitis et al. |  Verhey Lab |  eLife
• The biased sidestepping of kinesin-3 KIF1A causes microtubule rotation in gliding assays.
  Mitra et al. |  Casademunt Lab |  Biophysical Journal
• Bacterial cells accumulate FtsZ to a fixed threshold to control cell-size homeostasis.
  Si et al. |  Jun Lab |  Current Biology
• Microtubules can organize into spindle-like arrays in the absence of motor proteins.
  Edozie et al. |  Ross Lab |  Soft Matter
• Actin filaments block the elongation of new microtubules at the centrosome.
  Inoue et al. |  Théry Lab |  The EMBO Journal
• Actin and keratin disassembly near the spindle midzone causes local cytoplasmic softening.
  Field et al. |  Mitchison Lab |  Current Biology
• The Ndc80 complex undergoes auto-inhibition by conformational folding.
  Scarborough et al. |  Davis and Asbury Labs |  eLife
• Cleared Xenopus extracts are active in peroxisome protein transport.
  Romano et al. |  Rapoport Lab |  Journal of Cell Biology

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