Send to

Choose Destination
See comment in PubMed Commons below
Cell. 1998 Apr 3;93(1):81-91.

Human T cell leukemia virus type 1 oncoprotein Tax targets the human mitotic checkpoint protein MAD1.

Author information

  • 1Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0460, USA.


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.

[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center