title: hNuf2 inhibition blocks stable kinetochore-microtubule attachment and induces mitotic cell death in HeLa cells.
abstract: Identification of proteins that couple kinetochores to spindle microtubules is critical for understanding how accurate chromosome segregation is achieved in mitosis. Here we show that the protein hNuf2 specifically functions at kinetochores for stable microtubule attachment in HeLa cells. When hNuf2 is depleted by RNA interference, spindle formation occurs normally as cells enter mitosis, but kinetochores fail to form their attachments to spindle microtubules and cells block in prometaphase with an active spindle checkpoint. Kinetochores depleted of hNuf2 retain the microtubule motors CENP-E and cytoplasmic dynein, proteins previously implicated in recruiting kinetochore microtubules. Kinetochores also retain detectable levels of the spindle checkpoint proteins Mad2 and BubR1, as expected for activation of the spindle checkpoint by unattached kinetochores. In addition, the cell cycle block produced by hNuf2 depletion induces mitotic cells to undergo cell death. These data highlight a specific role for hNuf2 in kinetochore-microtubule attachment and suggest that hNuf2 is part of a molecular linker between the kinetochore attachment site and tubulin subunits within the lattice of attached plus ends.
authors.affiliation: University of North Carolina at Chapel Hill, Department of Biology, Chapel Hill, NC 27599, USA. jgdeluca@email.unc.edu
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: DeLuca
authors.forename: Ben
authors.initials: B
authors.lastname: Moree
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Hickey
authors.forename: John V
authors.initials: JV
authors.lastname: Kilmartin
authors.forename: E D
authors.initials: ED
authors.lastname: Salmon
mesh_terms: D002135:Calcium-Binding Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D016923:Cell Death / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D004398:Dyneins / Q000378:metabolism; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D064246:Mad2 Proteins; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D012097:Repressor Proteins; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; C490197:NUF2 protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D012097:Repressor Proteins; C068688:centromere protein E; D011494:Protein Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; D004398:Dyneins