title: Hook is an adapter that coordinates kinesin-3 and dynein cargo attachment on early endosomes.
abstract: Bidirectional membrane trafficking along microtubules is mediated by kinesin-1, kinesin-3, and dynein. Several organelle-bound adapters for kinesin-1 and dynein have been reported that orchestrate their opposing activity. However, the coordination of kinesin-3/dynein-mediated transport is not understood. In this paper, we report that a Hook protein, Hok1, is essential for kinesin-3- and dynein-dependent early endosome (EE) motility in the fungus Ustilago maydis. Hok1 binds to EEs via its C-terminal region, where it forms a complex with homologues of human fused toes (FTS) and its interactor FTS- and Hook-interacting protein. A highly conserved N-terminal region is required to bind dynein and kinesin-3 to EEs. To change the direction of EE transport, kinesin-3 is released from organelles, and dynein binds subsequently. A chimaera of human Hook3 and Hok1 rescues the hok1 mutant phenotype, suggesting functional conservation between humans and fungi. We conclude that Hok1 is part of an evolutionarily conserved protein complex that regulates bidirectional EE trafficking by controlling attachment of both kinesin-3 and dynein.
authors.affiliation: School of Biosciences, University of Exeter, Exeter EX4 4QD, England, UK.
authors.forename: Ewa
authors.initials: E
authors.lastname: Bielska
authors.forename: Martin
authors.initials: M
authors.lastname: Schuster
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Roger
authors.forename: Adokiye
authors.initials: A
authors.lastname: Berepiki
authors.forename: Darren M
authors.initials: DM
authors.lastname: Soanes
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Talbot
authors.forename: Gero
authors.initials: G
authors.lastname: Steinberg
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004398:Dyneins / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D005656:Fungal Proteins / Q000378:metabolism*; D016547:Kinesins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D014588:Ustilago / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D004398:Dyneins; D016547:Kinesins