Caspase-dependant activation of chymotrypsin-like proteases mediates nuclear events during Jurkat T cell apoptosis.
Apoptosis involves a cascade of biochemical and morphological changes resulting in the systematic disintegration of the cell. Caspases are central mediators of this process. Supporting and primary roles for serine proteases as pro-apoptotic mediators have also been highlighted. Evidence for such roles comes largely from the use of pharmacological inhibitors; as a consequence information regarding their apoptotic function and biochemical properties has been limited. Here, we circumvented limitations associated with traditional serine protease inhibitors through use of a fluorescently labelled inhibitor of serine proteases (FLISP) that allowed for analysis of the specificity, regulation and positioning of apoptotic serine proteases within a classical apoptotic cascade. We demonstrate that staurosporine triggers a caspase-dependant induction of chymotrypsin-like activity in the nucleus of apoptotic Jurkat T cells. We show that serine protease activity is required for the generation of late stage nuclear events including condensation, fragmentation and DNA degradation. Furthermore, we reveal caspase-dependant activation of two chymotrypsin-like protein species that we hypothesize mediate cell death-associated nuclear events.
O'Connell
A R
AR
National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland.
Lee
B W
BW
Stenson-Cox
C
C
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology*; D002918:Chymotrypsin / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D004789:Enzyme Activation; D005456:Fluorescent Dyes; D006801:Humans; D019169:Jurkat Cells / Q000166:cytology / Q000201:enzymology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D013379:Substrate Specificity
D061945:Caspase Inhibitors; D005456:Fluorescent Dyes; D015842:Serine Proteinase Inhibitors; D002918:Chymotrypsin; D020169:Caspases; D019311:Staurosporine