title: Mars promotes dTACC dephosphorylation on mitotic spindles to ensure spindle stability.
abstract: Microtubule-associated proteins (MAPs) ensure the fidelity of chromosome segregation by controlling microtubule (MT) dynamics and mitotic spindle stability. However, many aspects of MAP function and regulation are poorly understood in a developmental context. We show that mars, which encodes a Drosophila melanogaster member of the hepatoma up-regulated protein family of MAPs, is essential for MT stabilization during early embryogenesis. As well as associating with spindle MTs in vivo, Mars binds directly to protein phosphatase 1 (PP1) and coimmunoprecipitates from embryo extracts with minispindles and Drosophila transforming acidic coiled-coil (dTACC), two MAPs that function as spindle assembly factors. Disruption of binding to PP1 or loss of mars function results in elevated levels of phosphorylated dTACC on spindles. A nonphosphorylatable form of dTACC is capable of rescuing the lethality of mars mutants. We propose that Mars mediates spatially controlled dephosphorylation of dTACC, which is critical for spindle stabilization.
authors.affiliation: Department of Zoology, Oxford University, Oxford OX1 3PS, England, UK.
authors.forename: Shengjiang
authors.initials: S
authors.lastname: Tan
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Lyulcheva
authors.forename: Jon
authors.initials: J
authors.lastname: Dean
authors.forename: Daimark
authors.initials: D
authors.lastname: Bennett
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D054645:Protein Phosphatase 1 / Q000378:metabolism; D021381:Protein Transport; D000074407:SAP90-PSD95 Associated Proteins; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C000614192:Mars protein, Drosophila; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D000074407:SAP90-PSD95 Associated Proteins; C404402:TACC protein, Drosophila; D054645:Protein Phosphatase 1