title: Bidirectional transport along microtubules.
abstract: Active transport by microtubule motors has a plethora of crucial roles in eukaryotic cells. Organelles often move bidirectionally, employing both plus-end and minus-end directed motors. Bidirectional motion is widespread and may allow dynamic regulation, error correction and the establishment of polarized organelle distributions. Emerging evidence suggests that motors for both directions are simultaneously present on cellular 'cargo', but that their activity is coordinated so that when plus-end motors are active, minus-end motors are not, and vice versa. Both the dynein cofactor dynactin and the Klarsicht (Klar) protein appear to be important for such coordination. The direction of net transport depends on the balance between plus-end directed and minus-end directed motion. In several model systems, factors crucial for setting this balance have now been identified, setting the stage for a molecular dissection of the underlying regulatory mechanisms. These analyses will likely provide insight into motor cooperation in general.
authors.affiliation: Rosenstiel Biomedical Research Center and Department of Biology, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA. welte@brandeis.edu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Welte
mesh_terms: D001693:Biological Transport, Active; D029721:Drosophila Proteins / Q000378:metabolism; D000072159:Dynactin Complex; D050356:Lipid Metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism* / Q000502:physiology; D010860:Pigments, Biological / Q000378:metabolism; D014780:Viruses / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D000072159:Dynactin Complex; D026901:Membrane Transport Proteins; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D010860:Pigments, Biological; C401521:klar protein, Drosophila