title: The Role of the UNC-82 Protein Kinase in Organizing Myosin Filaments in Striated Muscle ofCaenorhabditis elegans.
abstract: We study the mechanisms that guide the formation and maintenance of the highly ordered actin-myosin cytoskeleton in striated muscle. The UNC-82 kinase ofCaenorhabditis elegansis orthologous to mammalian kinases ARK5/NUAK1 and SNARK/NUAK2. UNC-82 localizes to the M-line, and is required for proper organization of thick filaments, but its substrate and mechanism of action are unknown. Antibody staining of three mutants with missense mutations in the UNC-82 catalytic domain revealed muscle structure that is less disorganized than in the nullunc-82(0), but contained distinctive ectopic accumulations not found inunc-82(0)These accumulations contain paramyosin and myosin B, but lack myosin A and myosin A-associated proteins, as well as proteins of the integrin-associated complex. Fluorescently tagged missense mutant protein UNC-82 E424K localized normally in wild type; however, inunc-82(0), the tagged protein was found in the ectopic accumulations, which we also show to label with recently synthesized paramyosin. Recruitment of wild-type UNC-82::GFP to aggregates of differing protein composition in five muscle-affecting mutants revealed that colocalization of UNC-82 and paramyosin does not require UNC-96, UNC-98/ZnF, UNC-89/obscurin, CSN-5, myosin A, or myosin B individually. Dosage effects in paramyosin mutants suggest that UNC-82 acts as part of a complex, in which its stoichiometric relationship with paramyosin is critical. UNC-82 dosage affects muscle organization in the absence of paramyosin, perhaps through myosin B. We present evidence that the interaction of UNC-98/ZnF with myosin A is independent of UNC-82, and that UNC-82 acts upstream of UNC-98/ZnF in a pathway that organizes paramyosin during thick filament assembly.
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410.
authors.forename: NaTasha R
authors.identifier: 0000-0002-4894-7442
authors.initials: NR
authors.lastname: Schiller
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Duchesneau
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410.
authors.forename: Latrisha S
authors.initials: LS
authors.lastname: Lane
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410.
authors.forename: April R
authors.identifier: 0000-0001-7484-1986
authors.initials: AR
authors.lastname: Reedy
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410.
authors.forename: Emily R
authors.initials: ER
authors.lastname: Manzon
authors.affiliation: Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410 pamela.hoppe@wmich.edu.
authors.forename: Pamela E
authors.identifier: 0000-0001-8361-5518
authors.initials: PE
authors.lastname: Hoppe
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D003599:Cytoskeleton / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D020125:Mutation, Missense; D009210:Myofibrils / Q000378:metabolism*; D024507:Nonmuscle Myosin Type IIA / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D029742:Caenorhabditis elegans Proteins; D009124:Muscle Proteins; C481656:UNC-98 protein, C elegans; D017346:Protein Serine-Threonine Kinases; C548137:Unc-82 protein, C elegans; D024507:Nonmuscle Myosin Type IIA
keywords: AMPK-related kinase; myosin; paramyosin; striated muscle; thick filament assembly