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Updated: Jan 23, 2026
High-resolution Imaging and Analysis of Individual Astral Microtubule Dynamics in Budding Yeast
Published on: April 20, 2017
NDP52 tunes cortical actin interaction with astral microtubules for accurate spindle orientation
Huijuan Yu1,2, Fengrui Yang1,3, Peng Dong4
1Hefei National Center for Physical Sciences at the Microscale & CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, 230026, China.
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.
Insights
NDP52 protein regulates cell division by remodeling the actin cytoskeleton. It recruits N-WASP to actin-rich vesicles, ensuring proper spindle orientation and chromosome segregation during mitosis.
Area of Science:
- Cell Biology
- Molecular Biology
- Cytoskeleton Dynamics
Background:
- Oriented cell divisions are crucial for development and are regulated by conserved pathways.
- Key regulators include Gαi, LGN, and NuMA, which control spindle orientation.
- The precise mechanisms linking cytoskeletal dynamics to spindle positioning are still being elucidated.
Purpose of the Study:
- To investigate the role of NDP52 in regulating spindle orientation.
- To elucidate the molecular mechanisms by which NDP52 influences the actin cytoskeleton during mitosis.
- To understand how NDP52 coordinates microtubule and actin dynamics for accurate chromosome segregation.
Main Methods:
- RNA interference (siRNA) to suppress NDP52 expression.
- Total Internal Reflection Fluorescence (TIRFM) microscopy to analyze actin dynamics.
- Biochemical assays to study protein-vesicle interactions and actin filament length.
- Immunofluorescence microscopy to observe spindle and microtubule organization.
Main Results:
- NDP52 suppression led to defects in astral microtubule growth and aberrant spindle orientation.
- NDP52 recruits N-WASP and regulates a subcortical F-actin ring structure.
- NDP52-containing vesicles bind phosphatidic acid and sequester N-WASP, controlling local actin polymerization.
- In vitro analyses showed NDP52 vesicles anchor N-WASP and shorten actin filaments.
Conclusions:
- NDP52 plays a critical role in spindle orientation by remodeling the polar cortical actin cytoskeleton.
- NDP52-containing vesicles regulate actin dynamics via N-WASP, ensuring spatiotemporal coordination between microtubules and actin.
- This mechanism is essential for precise chromosome segregation and mitotic progression in metazoans, representing an evolutionarily elaborated machinery.
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