title: A novel interaction between Rab7b and actomyosin reveals a dual role in intracellular transport and cell migration.
abstract: Rab proteins are small GTPases that regulate transport between the different compartments of the endomembrane system in eukaryotic cells. Here, we show that Rab7b, a Rab that controls the transport between late endosomes and the trans Golgi network, interacts directly with myosin II. We illustrate the functional relevance of this interaction, demonstrating that myosin II mediates the transport of Rab7b endosomes, as Rab7b dynamics are strongly affected after myosin II depletion or inhibition. We also demonstrate that a member of the Rab family regulates actin remodeling and, consequently, influences cell adhesion, polarization and migration. We find the molecular mechanism by which Rab7b influences stress fiber formation - through controlling the activation status of the small GTPase RhoA and therefore influencing myosin light chain phosphorylation. Our findings reveal a newly identified role for Rab proteins outside of their canonical role in intracellular trafficking, identifying Rab7b as a coordinator of cytoskeletal organization.
authors.affiliation: Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway.
authors.forename: Marita
authors.initials: M
authors.lastname: Borg
authors.affiliation: Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway oddmund.bakke@ibv.uio.no c.a.m.progida@ibv.uio.no.
authors.forename: Oddmund
authors.initials: O
authors.lastname: Bakke
authors.affiliation: Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway oddmund.bakke@ibv.uio.no c.a.m.progida@ibv.uio.no.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Progida
mesh_terms: D000205:Actomyosin / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D011992:Endosomes / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D010766:Phosphorylation; D021381:Protein Transport; D014162:Transfection; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000090802:rab7 GTP-Binding Proteins
chemical_list: D000090802:rab7 GTP-Binding Proteins; D000205:Actomyosin; D020691:rab GTP-Binding Proteins
keywords: Actomyosin; Endosomes; Rab proteins; Rab7b