Unravelling the molecular basis of the dominant negative effect of myosin XI tails on P-bodies

The directional movement and positioning of organelles and macromolecules is essential for regulating and maintaining cellular functions in eukaryotic cells. In plants, these processes are actin-based and driven by class XI myosins, which transport various cargos in a directed manner. As the analysis of myosin function is challenging due to high levels of redundancy, dominant negative acting truncated myosins have frequently been used to study intracellular transport processes. A comparison of the dominant negative effect of the coiled-coil domains and the GTD domains revealed a much stronger inhibition of P-body movement by the GTD domains. In addition, we show that the GTD domain does not inhibit P-body movement when driven by a hybrid myosin in which the GTD domain was replaced by DCP2. These data suggest that the dominant negative effect of myosin tails involves a competition of the GTD domains for cargo binding sites.

Automated summary

In eukaryotic cells, the directional movement and positioning of organelles and macromolecules are regulated by actin-based processes driven by class XI myosins in plants. Analysis of myosin function is challenging due to redundancy, leading to the use of dominant negative acting truncated myosins. Comparing the dominant negative effect of coiled-coil domains and GTD domains revealed a stronger inhibition of P-body movement by GTD domains, suggesting a competition for cargo binding sites.