title: The dynamic properties of intermediate filaments during organelle transport.
abstract: Intermediate filament (IF) dynamics during organelle transport and their role in organelle movement were studied using Xenopus laevis melanophores. In these cells, pigment granules (melanosomes) move along microtubules and microfilaments, toward and away from the cell periphery in response to alpha-melanocyte stimulating hormone (alpha-MSH) and melatonin, respectively. In this study we show that melanophores possess a complex network of vimentin IFs which interact with melanosomes. IFs form an intricate, honeycomb-like network that form cages surrounding individual and small clusters of melanosomes, both when they are aggregated and dispersed. Purified melanosome preparations contain a substantial amount of vimentin, suggesting that melanosomes bind to IFs. Analyses of individual melanosome movements in cells with disrupted IF networks show increased movement of granules in both anterograde and retrograde directions, further supporting the notion of a melanosome-IF interaction. Live imaging reveals that IFs, in turn, become highly flexible as melanosomes disperse in response to alpha-MSH. During the height of dispersion there is a marked increase in the rate of fluorescence recovery after photobleaching of GFP-vimentin IFs and an increase in vimentin solubility. These results reveal a dynamic interaction between membrane bound pigment granules and IFs and suggest a role for IFs as modulators of granule movement.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Harvard University, Boston, MA, USA.
authors.forename: Lynne
authors.initials: L
authors.lastname: Chang
authors.forename: Kari
authors.initials: K
authors.lastname: Barlan
authors.forename: Ying-Hao
authors.initials: YH
authors.lastname: Chou
authors.forename: Boris
authors.initials: B
authors.lastname: Grin
authors.forename: Margot
authors.initials: M
authors.lastname: Lakonishok
authors.forename: Anna S
authors.initials: AS
authors.lastname: Serpinskaya
authors.forename: Dale K
authors.initials: DK
authors.lastname: Shumaker
authors.forename: Harald
authors.initials: H
authors.lastname: Herrmann
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Gelfand
authors.forename: Robert D
authors.initials: RD
authors.lastname: Goldman
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007382:Intermediate Filaments / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008547:Melanophores / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D020460:Melanosomes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008550:Melatonin / Q000494:pharmacology; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008954:Models, Biological; D012995:Solubility / Q000187:drug effects; D014746:Vimentin / Q000378:metabolism; D014982:Xenopus laevis / Q000378:metabolism*; D000521:alpha-MSH / Q000494:pharmacology
chemical_list: D014746:Vimentin; D049452:Green Fluorescent Proteins; D000521:alpha-MSH; D008550:Melatonin