RESUMO
Photomorphogenesis is a light-dependent plant growth and development program. As the core regulator of photomorphogenesis, ELONGATED HYPOCOTYL 5 (HY5) is affected by dynamic changes in its transcriptional activity and protein stability; however, little is known about the mediators of these processes. Here, we identified PHOTOREGULATORY PROTEIN KINASE 1 (PPK1), which interacts with and phosphorylates HY5 in Arabidopsis, as one such mediator. The phosphorylation of HY5 by PPK1 is essential to establish high-affinity binding with B-BOX PROTEIN 24 (BBX24) and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), which inhibit the transcriptional activity and promote the degradation of HY5, respectively. As such, PPKs regulate not only the binding of HY5 to its target genes under light conditions but also HY5 degradation when plants are transferred from light to dark. Our data identify a PPK-mediated phospho-code on HY5 that integrates the molecular mechanisms underlying the regulation of HY5 to precisely control plant photomorphogenesis.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fatores de Transcrição de Zíper de Leucina Básica , Regulação da Expressão Gênica de Plantas , Luz , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fosforilação , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Morfogênese/efeitos da radiação , Proteínas Quinases/metabolismo , Proteínas Quinases/genética , Proteínas RepressorasRESUMO
The present study aimed to evaluate the antitumor effects of MAGI2-AS3 and its mechanism in liver cancer. Cancer tissues and adjacent nontumor tissues were collected, and lncRNAs were analyzed via chip assay. The correlation between MAGEI2-AS3 and patient pathology and prognosis was then analyzed. Bel-7402 and Huh-7 cell lines were also used in our study. For the in vitro study, MTT assay, flow cytometry, transwell assay, and wound healing assay were conducted to evaluate hepatic cancer cell (Bel-7402 and Huh-7) proliferation, apoptosis, invasion, and migration. The relative mechanisms were evaluated by Western blot (WB) and cellular immunofluorescence. The correlation among MAGI2-AS3, miRNA-23a-3p, and PTEN was determined by a dual-luciferase reporter assay. The expression of lncRNA MAGI2-AS3 was significantly downregulated in tumor tissues. MAGI2-AS3 expression was closely correlation with HCC patient's clinicopathology and prognosis and prognosis. In the cell experiment, compared with the negative control (NC) group, MAGI2-AS3 overexpression reduced cell proliferation, invasion, and migration and increased cell apoptosis in Bel-7402 and Huh-7 cell lines. However, when Bel-7402 and Huh-7 cells were transfected with miRNA-23a-3p, their biological activities (proliferation, invasion, and migration) were significantly increased. Through WB assay, MAGI2-AS3 could increase PTEN and depress p-AKT and MMP-9 protein expressions via miRNA-23a-3p suppression. The dual-luciferase reporter assay revealed that MAGI2-AS3 directly targeted miRNA-23a-3p and that miRNA-23a-3p could target PTEN. MAGI2-AS3 might be a potential therapeutic target for liver cancer owing to its regulation by the miRNA-23a-3p/PTEN axis.
