NDP52 tunes cortical actin interaction with astral microtubules for accurate spindle orientation

Cell Res. 2019 Aug;29(8):666-679. doi: 10.1038/s41422-019-0189-9. Epub 2019 Jun 14.

Abstract

Oriented cell divisions are controlled by a conserved molecular cascade involving Gαi, LGN, and NuMA. Here, we show that NDP52 regulates spindle orientation via remodeling the polar cortical actin cytoskeleton. siRNA-mediated NDP52 suppression surprisingly revealed a ring-like compact subcortical F-actin architecture surrounding the spindle in prophase/prometaphase cells, which resulted in severe defects of astral microtubule growth and an aberrant spindle orientation. Remarkably, NDP52 recruited the actin assembly factor N-WASP and regulated the dynamics of the subcortical F-actin ring in mitotic cells. Mechanistically, NDP52 was found to bind to phosphatidic acid-containing vesicles, which absorbed cytoplasmic N-WASP to regulate local filamentous actin growth at the polar cortex. Our TIRFM analyses revealed that NDP52-containing vesicles anchored N-WASP and shortened the length of actin filaments in vitro. Based on these results we propose that NDP52-containing vesicles regulate cortical actin dynamics through N-WASP to accomplish a spatiotemporal regulation between astral microtubules and the actin network for proper spindle orientation and precise chromosome segregation. In this way, intracellular vesicles cooperate with microtubules and actin filaments to regulate proper mitotic progression. Since NDP52 is absent from yeast, we reason that metazoans have evolved an elaborate spindle positioning machinery to ensure accurate chromosome segregation in mitosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actins / metabolism*
  • Chromosome Segregation / genetics
  • Cytoplasmic Vesicles / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Microtubules / metabolism*
  • Mitosis / genetics*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • RNA Interference
  • Spindle Apparatus / metabolism*
  • Wiskott-Aldrich Syndrome Protein, Neuronal / metabolism

Substances

  • Actins
  • CALCOCO2 protein, human
  • Nuclear Proteins
  • WASL protein, human
  • Wiskott-Aldrich Syndrome Protein, Neuronal