title: Active diffusion and microtubule-based transport oppose myosin forces to position organelles in cells.
abstract: Even distribution of peroxisomes (POs) and lipid droplets (LDs) is critical to their role in lipid and reactive oxygen species homeostasis. How even distribution is achieved remains elusive, but diffusive motion and directed motility may play a role. Here we show that in the fungus Ustilago maydis ∼95% of POs and LDs undergo diffusive motions. These movements require ATP and involve bidirectional early endosome motility, indicating that microtubule-associated membrane trafficking enhances diffusion of organelles. When early endosome transport is abolished, POs and LDs drift slowly towards the growing cell end. This pole-ward drift is facilitated by anterograde delivery of secretory cargo to the cell tip by myosin-5. Modelling reveals that microtubule-based directed transport and active diffusion support distribution, mobility and mixing of POs. In mammalian COS-7 cells, microtubules and F-actin also counteract each other to distribute POs. This highlights the importance of opposing cytoskeletal forces in organelle positioning in eukaryotes.
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.|Mathematics, University of Exeter, North Park Road, Exeter EX4 4QF, UK.
authors.forename: Congping
authors.initials: C
authors.lastname: Lin
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Schuster
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Sofia Cunha
authors.initials: SC
authors.lastname: Guimaraes
authors.affiliation: Mathematics, University of Exeter, North Park Road, Exeter EX4 4QF, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Ashwin
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Schrader
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Metz
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Christian
authors.initials: C
authors.lastname: Hacker
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Gurr
authors.affiliation: School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Gero
authors.initials: G
authors.lastname: Steinberg
mesh_terms: D000199:Actins / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001692:Biological Transport; D001696:Biomechanical Phenomena; D019556:COS Cells; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D004058:Diffusion; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D025301:Hyphae / Q000378:metabolism / Q000648:ultrastructure; D066292:Lipid Droplets / Q000378:metabolism* / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism* / Q000648:ultrastructure; D020675:Peroxisomes / Q000378:metabolism* / Q000648:ultrastructure; D014588:Ustilago / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000199:Actins; D009218:Myosins