Processing-Body Movement in Arabidopsis Depends on an Interaction between Myosins and DECAPPING PROTEIN1. Issue 4 (13th February 2014) - Steffens, Alexandra
Abstract : Intracellular transport of processing bodies along actin involves an evolutionarily conserved mechanism of direct interaction between myosins and the processing body core P1 . Abstract: Processing (P )-bodies are cytoplasmic RNA protein aggregates responsible for the storage, degradation, and quality control of translationally repressed messenger RNAs in eukaryotic cells. In mammals, P -body-related RNA and protein exchanges are actomyosin dependent, whereas P -body movement requires intact microtubules. In contrast, in plants, P -body motility is actin based. In this study, we show the direct interaction of the P -body core component DECAPPING PROTEIN1 (DCP1) with the tails of different unconventional myosins in Arabidopsis ( Arabidopsis thaliana ). By performing coexpression studies with AtDCP1, dominant-negative myosin fragments, as well as functional full-length myosin XI-K, the association of P -bodies and myosins was analyzed in detail. Finally, the combination of mutant analyses and characterization of P -body movement patterns showed that myosin XI-K is essential for fast and directed P -body transport. Together, our data indicate that P -body movement in plants is governed by myosin XI members through direct binding to AtDCP1 rather than through an adapter protein, as known for membrane-coated organelles. Interspecies and intraspecies interaction approaches with mammalian and yeast protein homologs suggest that this mechanism is evolutionarily conserved among eukaryotes.