Poly(ADP-ribose) polymerase cleavage during apoptosis: when and where?

• Poly(ADP-ribose) polymerase-1 (PARP-1) plays the active role of "nick sensor" during DNA repair and apoptosis, when it synthesizes ADP-ribose from NAD(+) in the presence of DNA strand breaks. Moreover, PARP-1 becomes a target of apoptotic caspases, which originate two proteolytic fragments of 89 and 24 kDa. The precise relationship between PARP-1 activation and degradation during apoptosis is still a matter of debate. In human Hep-2 cells driven to apoptosis by actinomycin D, we have monitored PARP-1 activity by the mAb 10H, which is specific for the ADP-ribose polymers, and we have observed that poly(ADP-ribose) synthesis is a very early response to the apoptotic stimulus. The analysis of the presence and fate of the p89 proteolytic fragment revealed that PARP-1 proteolysis by caspases is concomitant with poly(ADP-ribose) synthesis and that p89 migrates from the nucleus into the cytoplasm in late apoptotic cells with advanced nuclear fragmentation.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Nyckelord

Apoptosis

Blotting

Western

Cell Line

Cell Nucleus

metabolism

Cytoplasm

metabolism

DNA Repair

Dactinomycin

pharmacology

Enzyme Activation

Flow Cytometry

Fluorescein-5-isothiocyanate

metabolism

Humans

Immunohistochemistry

Indicators and Reagents

pharmacology

Microscopy

Confocal

Microscopy

Fluorescence

Phosphatidylserines

chemistry

Poly(ADP-ribose) Polymerases

metabolism

Propidium

pharmacology

Protein Binding

Protein Synthesis Inhibitors

pharmacology

Time Factors

Tumor Cells

Cultured

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