XBP1 negatively regulates CENPF expression via recruiting ATF6α to the promoter during ER stress

Tao Shen; Yan Li; Shuang Liang; Zhiguang Chen

doi:10.1186/s12935-020-01553-9

XBP1 negatively regulates CENPF expression via recruiting ATF6α to the promoter during ER stress

Cancer Cell Int. 2020 Sep 22:20:459. doi: 10.1186/s12935-020-01553-9. eCollection 2020.

Authors

Tao Shen¹, Yan Li^{2

3}, Shuang Liang⁴, Zhiguang Chen¹

Affiliations

¹ Department of Orthopedics, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004 People's Republic of China.
² Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, 110122 People's Republic of China.
³ Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037 USA.
⁴ Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455 USA.

Abstract

Background: Centromere protein F (CENPF) is a key component of the kinetochore complex involved in mitosis, cell differentiation and cellular response to stresses. However, the alteration of CENPF in response to endoplasmic reticulum (ER) stress has not been well described. In the present study, we investigate CENPF regulation in response to ER stress.

Methods: Quantitative real-time polymerase chain reaction and western blotting were used to determine CENPF expression under ER stress. Luciferase activity analysis was performed to investigate the promoter regions contributing to CENPF transcription in response to TG. Chromatin immunoprecipitation (ChIP) and ChIP Re-IP assays were used to determine if X-box binding protein 1 (XBP1) and/or activating transcription factor 6α (ATF6α) bind in the CENPF promoter region. Cell apoptosis and proliferation were analyzed using TUNEL, cell growth and clonogenic assays.

Results: CENPF expression is dramatically reduced under ER stress induced by thapsigargin (TG), brefeldin A (BFA), or tunicamycin (TM) and this downregulation of CENPF expression was dependent on XBP1 and ATF6α. Luciferase activity analysis of the truncated CENPF promoter indicates that regions from bases - 679 to - 488 and from - 241 to - 78 in the CENPF promoter were sensitive to TG treatment. Additionally, ChIP and ChIP Re-IP assays reveal that XBP1 and ATF6α were assembled on the same regions of CENPF promoter. Notably, we identify two XBP1 binding sequences at positions - 567 and - 192, to which XBP1 binding was enhanced by TG. Finally, CENPF overexpression inhibits cell apoptosis and promotes cell proliferation in response to ER stress.

Conclusion: In summary, these results demonstrate that ER stress plays a crucial role in CENPF expression, and XBP1 may up-regulate DNA-binding affinities after TG treatment to the promoter of CENPF. These findings may contribute to the understanding of the molecular mechanism of CENPF regulation.

Keywords: ATF6α; CENPF; ER stress; Expression regulation; XBP1.