Caspase-mediated cleavage of X-ray repair cross-complementing group 4 promotes apoptosis by enhancing nuclear translocation of caspase-activated DNase
- Department of Biochemistry I, School of Medicine, Kanazawa Medical University, Kahoku-gun, Ishikawa 920-0293 (Japan)
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550 (Japan)
- Department of Physics, General Education Department, Kanazawa Medical University, Kahoku-gun, Ishikawa 920-0293 (Japan)
- Division of Molecular and Cell Biology, Medical Research Institute, Kanazawa Medical University, Kahoku-gun, Ishikawa 920-0293 (Japan)
Highlights: • XRCC4 and its cleavage by caspases promote staurosporine-induced apoptosis. • XRCC4 cleavage enhances staurosporine-induced nuclear import of CAD. • XRCC4 facilitates SRPK1-mediated SRSF1 activation, which reduces ICAD-S mRNA. • XRCC4-dependent reduction of ICAD-S stimulates the nuclear import of CAD. • XRCC4 also enhances apoptosis triggered by paclitaxel or vincristine. X-ray repair cross-complementing group 4 (XRCC4), a repair protein for DNA double-strand breaks, is cleaved by caspases during apoptosis. In this study, we examined the role of XRCC4 in apoptosis. Cell lines, derived from XRCC4-deficient M10 mouse lymphoma cells and stably expressing wild-type XRCC4 or caspase-resistant XRCC4, were established and treated with staurosporine (STS) to induce apoptosis. In STS-induced apoptosis, expression of wild-type, but not caspase-resistant, XRCC4 in XRCC4-deficient cells enhanced oligonucleosomal DNA fragmentation and the appearance of TUNEL-positive cells by promoting nuclear translocation of caspase-activated DNase (CAD), a major nuclease for oligonucleosomal DNA fragmentation. CAD activity is reportedly regulated by the ratio of two inhibitor of CAD (ICAD) splice variants, ICAD-L and ICAD-S mRNA, which, respectively, produce proteins with and without the ability to transport CAD into the nucleus. The XRCC4-dependent promotion of nuclear import of CAD in STS-treated cells was associated with reduction of ICAD-S mRNA and protein, and enhancement of phosphorylation and nuclear import of serine/arginine-rich splicing factor (SRSF) 1. These XRCC4-dependent, apoptosis-enhancing effects were canceled by depletion of SRSF1 or SR protein kinase (SRPK) 1. In addition, overexpression of SRSF1 in XRCC4-deficient cells restored the normal level of apoptosis, suggesting that SRSF1 functions downstream of XRCC4 in activating CAD. This XRCC4-dependent, SRPK1/SRSF1-mediated regulatory mechanism was conserved in apoptosis in Jurkat human leukemia cells triggered by STS, and by two widely used anti-cancer agents, Paclitaxel and Vincristine. These data imply that the level of XRCC4 expression could be used to predict the effects of apoptosis-inducing drugs in cancer treatment.
- OSTI ID:
- 23082494
- Journal Information:
- Experimental Cell Research, Vol. 362, Issue 2; Other Information: Copyright (c) 2017 Elsevier Inc. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phylogenomics of caspase-activated DNA fragmentation factor
B1-induced caspase-independent apoptosis in MCF-7 cells is mediated by down-regulation of Bcl-2 via p53 binding to P2 promoter TATA box