title: Caspase-3 is required in the apoptotic disintegration of the nuclear matrix.
abstract: Apoptotic breakdown of cellular structures is largely mediated by caspases. One target of degradation is a proteinaceous framework of the nucleus termed the nuclear matrix. We compared the apoptotic changes of the nuclear matrix in staurosporine-treated caspase-3-deficient MCF-7 cells transfected with intact CASP-3 gene (MCF-7c3) or an empty vector (MCF-7v) as a control. Nuclear Mitotic Apparatus protein (NuMA), lamin A/C and lamin B were used as markers for internal nuclear matrix and peripheral nuclear lamina, respectively. In both cell lines, staurosporine induced rapid cytoplasmic shrinkage and partial chromatin condensation. MCF-7c3 cells formed apoptotic bodies, whereas MCF-7v cells did not. NuMA and lamins were actively cleaved in MCF-7c3 cells following caspase-3 activation, but only minimal or no cleavage was detected in MCF-7v cells. Interestingly, lamin B but not lamin A/C was relocated into cytoplasmic granules in apoptotic MCF-7v cells. Pancaspase inhibitor, z-VAD-fmk, prevented the apoptotic changes, while caspase-3 inhibitor, z-DEVD-fmk, induced lamin B granules in both cell lines. These results show that caspase-3 is involved in the cleavage of NuMA and lamins either directly or by activating other proteases. This may be essential for disintegration of the nuclear structure during apoptosis.
authors.affiliation: Department of Pathology, University of Turku, MediCity Research Laboratory, Tykistökatu 6 A, 4th floor, FIN-20520 Turku, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Kivinen
authors.forename: Markku
authors.initials: M
authors.lastname: Kallajoki
authors.forename: Pekka
authors.initials: P
authors.lastname: Taimen
mesh_terms: D000590:Amino Acid Chloromethyl Ketones; D034961:Antigens, Nuclear; D017209:Apoptosis; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000172:deficiency / Q000502:physiology*; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000201:enzymology*; D002843:Chromatin / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D034904:Lamin Type A / Q000378:metabolism; D034921:Lamin Type B / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D034961:Antigens, Nuclear; D061945:Caspase Inhibitors; D018797:Cell Cycle Proteins; D002843:Chromatin; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D034904:Lamin Type A; D034921:Lamin Type B; C050045:NUMA1 protein, human; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C440308:lamin C; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine