Kinesin-3 and dynein mediate microtubule-dependent co-transport of mRNPs and endosomes

Baumann, Sebastian; Pohlmann, Thomas; Jungbluth, Marc; Brachmann, Andreas und Feldbrügge, Michael (2012): Kinesin-3 and dynein mediate microtubule-dependent co-transport of mRNPs and endosomes. In: Journal of Cell Science, Bd. 125, Nr. 11: S. 2740-2752

Abstract

Long-distance transport of mRNAs is important in determining polarity in eukaryotes. Molecular motors shuttle large ribonucleoprotein complexes (mRNPs) containing RNA-binding proteins and associated factors along microtubules. However, precise mechanisms including the interplay of molecular motors and a potential connection to membrane trafficking remain elusive. Here, we solve the motor composition of transported mRNPs containing the RNA-binding protein Rrm4 of the pathogen Ustilago maydis. The underlying transport process determines the axis of polarity in infectious filaments. Plus-end-directed Kin3, a kinesin-3 type motor, mediates anterograde transport of mRNPs and is also present in transport units moving retrogradely. Split dynein Dyn1–Dyn2 functions in retrograde movement of mRNPs. Plus-end-directed conventional kinesin Kin1 is indirectly involved by transporting minus-end-directed dynein back to plus ends. Importantly, we additionally demonstrate that Rrm4-containing mRNPs colocalise with the t-SNARE Yup1 on shuttling endosomes and that functional endosomes are essential for mRNP movement. Either loss of Kin3 or removal of its lipid-binding pleckstrin-homology domain abolishes Rrm4-dependent movement without preventing colocalisation of Rrm4 and Yup1-positive endosomes. In summary, we uncovered the combination of motors required for mRNP shuttling along microtubules. Furthermore, intimately linked co-transport of endosomes and mRNPs suggests vesicle hitchhiking as mode of mRNP transport.

• Dokumententyp: Zeitschriftenartikel
• Publikationsform: Publisher's Version
• Keywords: RNA recognition motif; Long-distance transport; Vesicle trafficking; Ustilago maydis
• Fakultät: Biologie > Department Biologie I
• Themengebiete: 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften; Biologie
• ISSN: 0021-9533
• Sprache: Englisch