KLHL4, a novel p53 target gene, inhibits cell proliferation by activating p21WAF/CDKN1A

• Published in: Biochemical and biophysical research communications Vol. 530; no. 3; pp. 588 - 596
• Main Authors: Choi, Seo-Hyun, Cho, Su-Yeon, Song, Jiyang, Hur, Man-Wook
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 24.09.2020
• Subjects: Cell proliferation; Cullin; DNA damage; KLHL4; p21; p53; Ubiquitination; Cell proliferation; Ubiquitination; DNA damage; KLHL4; p21; p53; Cullin
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2020.07.100

KLHL4 is a member of the KLHL protein family, many of whom bind the Cul3 E3 ligase, and mediate the ubiquitination of interacting proteins. The KLHL4 gene, localized on the X chromosome, associates with a disorder known as X-linked cleft palate (CPX). However, the biological functions of KLHL4 are largely unknown. In this study, microarray analysis of HEK293A embryonic kidney cells, expressing ectopic p53, showed a 3-fold increase of KLHL4 mRNA. Moreover, both KLHL4 mRNA and protein expression were elevated by p53 or DNA damage, suggesting that KLHL4 might be a p53 target gene. We also found that KLHL4 activates transcription of p21WAF/CDKN1A, a p53 target gene encoding a major negative regulator of the cell-cycle. KLHL4 interacted with p53 to increase its binding to p53 response element of the p21WAF/CDKN1A gene, resulting in transcriptional upregulation. Furthermore, we observed that KLHL4 can interact with the Cul3 ubiquitin ligase, to possibly play a role in ubiquitin-mediated proteasomal degradation, and Klhl4 knocked-out MEF mouse embryonic fibroblasts proliferated faster than WT MEF cells. These results suggest that KLHL4 upregulation by p53 may inhibit cell proliferation, by activating p21WAF/CDKN1A. •KLHL4 mRNA and protein expression are elevated by p53 or DNA damage.•KLHL4 activates transcription of p21WAF/CDKN1A, a major negative regulator of the cell-cycle.•KLHL4 interacts with p53 to increase its binding to p53RE2 of the p21WAF/CDKN1A gene.•KLHL4 can interact with the Cul3 ubiquitin ligase.•Klhl4 knocked-out MEF mouse embryonic fibroblasts proliferates faster than WT MEF cells.