title: Granzyme M targets topoisomerase II alpha to trigger cell cycle arrest and caspase-dependent apoptosis.
abstract: Cytotoxic lymphocyte protease granzyme M (GrM) is a potent inducer of tumor cell death. The apoptotic phenotype and mechanism by which it induces cell death, however, remain poorly understood and controversial. Here, we show that GrM-induced cell death was largely caspase-dependent with various hallmarks of classical apoptosis, coinciding with caspase-independent G2/M cell cycle arrest. Using positional proteomics in human tumor cells, we identified the nuclear enzyme topoisomerase II alpha (topoIIα) as a physiological substrate of GrM. Cleavage of topoIIα by GrM at Leu(1280) separated topoIIα functional domains from the nuclear localization signals, leading to nuclear exit of topoIIα catalytic activity, thereby rendering it nonfunctional. Similar to the apoptotic phenotype of GrM, topoIIα depletion in tumor cells led to cell cycle arrest in G2/M, mitochondrial perturbations, caspase activation, and apoptosis. We conclude that cytotoxic lymphocyte protease GrM targets topoIIα to trigger cell cycle arrest and caspase-dependent apoptosis.
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: S A H
authors.initials: SA
authors.lastname: de Poot
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: K W
authors.initials: KW
authors.lastname: Lai
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: van der Wal
authors.affiliation: 1] Department of Medical Protein Research,VIB, Ghent, B-9000, Belgium [2] Department of Biochemistry, Ghent University, Ghent B-9000, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Plasman
authors.affiliation: 1] Department of Medical Protein Research,VIB, Ghent, B-9000, Belgium [2] Department of Biochemistry, Ghent University, Ghent B-9000, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Van Damme
authors.affiliation: Centre for Haematology, Faculty of Medicine, Imperial College London, London, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Porter
authors.affiliation: 1] Department of Medical Protein Research,VIB, Ghent, B-9000, Belgium [2] Department of Biochemistry, Ghent University, Ghent B-9000, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Gevaert
authors.affiliation: 1] Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands [2] Laboratory for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: Bovenschen
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D019556:COS Cells; D020169:Caspases / Q000378:metabolism*; D059447:Cell Cycle Checkpoints / Q000502:physiology*; D016923:Cell Death; D002522:Chlorocebus aethiops; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D053804:Granzymes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000201:enzymology; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D053804:Granzymes; D020169:Caspases; D004250:DNA Topoisomerases, Type II