A natural killer cell granule protein that induces DNA fragmentation and apoptosis.

We report the purification from a rat natural killer large granular lymphocyte leukemia of a 32-kD granule protein that induces rapid DNA fragmentation and apoptosis

L Shi; R P Kraut; R Aebersold; A H Greenberg


Scholarcy highlights

  • We report here the purification from the granules of a rat NK 1 LGL leukemia of a 32-kD protein that induces very rapid DNA fragmentation with nuclear collapse and apoptosis in tumor target cells
  • R N K cells as described previously, and two aliquots of 0.75 x 101~cell equivalents were solubilized in 2 M NaC1 and subjected to fast protein liquid chromatography chromatography
  • The possibility that the DNA fragmentation required the presence of cytolysin from the second peak was confirmed utilizing purified cytolysin prepared by sequential Ultragel AcA54 and heparin-agarose chromatography as described earlier or phenyl superose and heparin-agarose as described in Materials and Methods
  • The structural homology of fragmentin to granzymes RNK protease 1 and cytotoxic T cell protease I suggested that its ability to induce DNA fragmentation was related to its proteolytic activity
  • The results of the present study show that the granules of an NK cell tumor line contain both cytolysin and a second 32-kD protein, fragmentin, that together can induce rapid DNA damage in target cells
  • In support of this hypothesis, we demonstrated that cytochalasin B, 2-deoxyglucose, and sodium azide can completely or partially block fragmentininduced DNA and membrane damage without reducing cytolysin activity

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