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Cooperation between microtubule- and actin-based motor proteins

S S Brown1

  • 1Department of Anatomy and Cell Biology, University of Michigan Medical School, Ann Arbor 48109, USA. susanbb@umich.edu

Annual Review of Cell and Developmental Biology
|December 28, 1999
PubMed

Insights

Organelle transport involves long-range and local delivery. A surprising physical interaction between class V myosins and kinesin motors has been discovered, linking two motor protein families in cellular transport.

Area of Science:

  • Cell Biology
  • Molecular Motors
  • Cytoskeletal Dynamics

Background:

  • Organelle transport is crucial for cellular function, often modeled as a two-step process involving microtubule-based long-range movement and actin-based local delivery.
  • Class V myosins are implicated as key actin-based motors in various cell types, including neurons and pigment cells.
  • Genetic studies in mice (dilute) and yeast (myo2) have highlighted the role of class V myosins in organelle transport, with yeast studies suggesting a supporting role for the kinesin-related protein Smy1p.

Purpose of the Study:

  • To investigate the relationship between actin-based motors (class V myosins) and microtubule-based motors (kinesins) in organelle transport.
  • To explore potential physical interactions between these distinct motor protein superfamilies.

Main Methods:

  • Analysis of genetic mutations affecting organelle transport in model organisms (mice and yeast).
  • Investigating genetic interactions between myosin and kinesin-related proteins.
  • Biochemical or cellular assays to detect physical interactions between motor proteins.

Main Results:

  • Evidence supports a model where class V myosins mediate local organelle delivery after long-range transport.
  • Mutations in class V myosins (dilute in mice, myo2 in yeast) impair organelle transport.
  • Genetic interactions in yeast suggest a supporting role for Smy1p (kinesin-related protein) in myosin-driven transport.
  • Crucially, direct physical interaction between class V myosins and kinesin or Smy1p has been observed in both mice and yeast.

Conclusions:

  • Class V myosins and kinesins are not only functionally linked but also physically interact, suggesting a coordinated mechanism for organelle transport.
  • This interaction bridges the microtubule and actin cytoskeletal systems, providing a more integrated understanding of intracellular transport.
  • The findings reveal a novel cross-talk between different motor protein families, impacting fundamental cellular processes.

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