Early endosome motility spatially organizes polysome distribution

Yujiro Higuchi, Peter Ashwin, Yvonne Roger, Gero Steinberg

Research output: Contribution to journalArticlepeer-review

96 Citations (Scopus)


Early endosomes (EEs) mediate protein sorting, and their cytoskeleton-dependent motility supports longdistance signaling in neurons. Here, we report an unexpected role of EE motility in distributing the translation machinery in a fungal model system. We visualize ribosomal subunit proteins and show that the large subunits diffused slowly throughout the cytoplasm (Dc,60S = 0.311 μm2/s), whereas entire polysomes underwent long-range motility along microtubules. This movement was mediated by "hitchhiking" on kinesin-3 and dyneindriven EEs, where the polysomes appeared to translate EE-associated mRNA into proteins. Modeling indicates that this motor-driven transport is required for even cellular distribution of newly formed ribosomes. Indeed, impaired EE motility in motor mutants, or their inability to bind EEs in mutants lacking the RNA-binding protein Rrm4, reduced ribosome transport and induced ribosome aggregation near the nucleus. As a consequence, cell growth was severely restricted. Collectively, our results indicate that polysomes associate with moving EEs and that "off- and reloading" distributes the protein translation machinery.

Original languageEnglish
Pages (from-to)343-357
Number of pages15
JournalJournal of Cell Biology
Issue number3
Publication statusPublished - Feb 3 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Cell Biology


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