title: Human T cell leukemia virus type 1 oncoprotein Tax targets the human mitotic checkpoint protein MAD1.
abstract: In searching for cellular targets of the HTLV-I oncoprotein Tax, we identified TXBP181, which we characterized as the human homolog of yeast mitotic checkpoint MAD1 protein. Evidence supporting TXBP181 as HsMAD1 includes sequence conservation with yeast MAD1, hyperphosphorylation during S/G2/M phases and upon treatment of cells with nocodazole, and binding to HsMAD2. HsMAD1 functions as a homodimer. It localizes to the centrosome during metaphase and to the spindle midzone and the midbody during anaphase and telophase. Expression of either Tax or a transdominant-negative TXBP181 results in multinucleated cells, a phenotype consistent with a loss of HsMAD1 function. We propose a model of viral transformation in which Tax targets TXBP181, thereby abrogating a mitotic checkpoint.
authors.affiliation: Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0460, USA.
authors.forename: D Y
authors.initials: DY
authors.lastname: Jin
authors.forename: F
authors.initials: F
authors.lastname: Spencer
authors.forename: K T
authors.initials: KT
authors.lastname: Jeang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins; D017124:Conserved Sequence; D016356:Gene Products, tax / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D015368:Human T-lymphotropic virus 1 / Q000378:metabolism*; D006801:Humans; D008322:Mammals; D008938:Mitosis; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016356:Gene Products, tax; C501382:MAD1 protein, S cerevisiae; C501384:MAD1L1 protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D015739:Nocodazole