The MAP3K2-ERK5 pathway upregulates cyclin D1 expression through histone H2A (Thr120) phosphorylation by VRK1

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Author(s)

    • Kato Masanori
    • Department of Biochemistry, Nagasaki University School of Medicine|Nagasaki University Graduate School of Biomedical Sciences
    • Takeshima Yukio
    • Department of Pathology, Hiroshima University Graduate School of Biomedical & Health Sciences
    • Amatya Vishwa Jeet
    • Department of Pathology, Hiroshima University Graduate School of Biomedical & Health Sciences
    • Higashi Miki
    • Department of Biochemistry, Nagasaki University School of Medicine
    • Ito Takashi
    • Department of Biochemistry, Nagasaki University School of Medicine|Nagasaki University Graduate School of Biomedical Sciences

Abstract

VRK1 plays a pivotal role in the upregulation of cyclin D1 (also known as CCND1) by phosphorylating histone H2A (Thr120) around its promoter region. However, the pathways or proteins that regulate this activity upstream of VRK1 remain unknown. It has been confirmed that after serum stimulation VRK1 is recruited to the cyclin D1 promoter region, and phosphorylation of the neighboring histone H2A (Thr120) is elevated. To clarify the upstream signals that regulate VRK1, we knocked down mitogen-activated protein kinases (MAPKs), including ERK5, MAP3K2, ERK1/2, JNK1/2, JNK3, and p38 in HeLa cells. We found that ERK5 knockdown decreases cyclin D1 expression, and this dependence on ERK5 was confirmed with the ERK5 inhibitors, BIX02188 and XMD8-92. Knockdown of MAP3K2, which is a well-known kinase acting upstream of the MEK5-ERK5 pathway, also reduced cyclin D1 expression, signifying the importance of the MAP3K2–ERK5 axis in regulating the expression of this gene. Next, evidence from chromatin immunoprecipitation qPCR (ChIP-qPCR) assays indicated that ERK5 or MAP3K2 knockdown reduces the recruitment of VRK1 and phosphorylation of H2A (Thr120) around the cyclin D1 promoter. Moreover, public microarray analysis of HeLa cells treated with either EGF or a DNA-damaging agent showed that ERK5 and cyclin D1 expression levels were significantly correlated in both treatments. Pathway analysis using the Ingenuity database supported our experimental observation that the MAP3K2– ERK5 pathway promotes cyclin D1 expression upstream of the VRK1 phosphorylation of H2A (Thr120). Finally, we showed that H2A (Thr120) phosphorylation is correlated with cyclin D1 expression in clinical tissue analysis. These results suggest that the MAP3K2–ERK5 pathway elevates cyclin D1 expression by recruiting VRK1 and elevating H2A (Thr120) phosphorylation in the cyclin D1 promoter region, which may be involved in dysregulated cell proliferation and cancer progression.

VRK1 plays a pivotal role in the upregulation of cyclin D1 (also known as CCND1) by phosphorylating histone H2A (Thr120) around its promoter region. However, the pathways or proteins that regulate this activity upstream of VRK1 remain unknown. It has been confirmed that after serum stimulation VRK1 is recruited to the cyclin D1 promoter region, and phosphorylation of the neighboring histone H2A (Thr120) is elevated. To clarify the upstream signals that regulate VRK1, we knocked down mitogen-activated protein kinases (MAPKs), including ERK5, MAP3K2, ERK1/2, JNK1/2, JNK3, and p38 in HeLa cells. We found that ERK5 knockdown decreases cyclin D1 expression, and this dependence on ERK5 was confirmed with the ERK5 inhibitors, BIX02188 and XMD8-92. Knockdown of MAP3K2, which is a well-known kinase acting upstream of the MEK5-ERK5 pathway, also reduced cyclin D1 expression, signifying the importance of the MAP3K2–ERK5 axis in regulating the expression of this gene. Next, evidence from chromatin immunoprecipitation qPCR (ChIP-qPCR) assays indicated that ERK5 or MAP3K2 knockdown reduces the recruitment of VRK1 and phosphorylation of H2A (Thr120) around the cyclin D1 promoter. Moreover, public microarray analysis of HeLa cells treated with either EGF or a DNA-damaging agent showed that ERK5 and cyclin D1 expression levels were significantly correlated in both treatments. Pathway analysis using the Ingenuity database supported our experimental observation that the MAP3K2– ERK5 pathway promotes cyclin D1 expression upstream of the VRK1 phosphorylation of H2A (Thr120). Finally, we showed that H2A (Thr120) phosphorylation is correlated with cyclin D1 expression in clinical tissue analysis. These results suggest that the MAP3K2– ERK5 pathway elevates cyclin D1 expression by recruiting VRK1 and elevating H2A (Thr120) phosphorylation in the cyclin D1 promoter region, which may be involved in dysregulated cell proliferation and cancer progression.

Journal

  • Acta Medica Nagasakiensia

    Acta Medica Nagasakiensia 62(1), 15-26, 2018

    Nagasaki University School of Medicine

Codes

  • NII Article ID (NAID)
    130007683941
  • Text Lang
    ENG
  • Article Type
    departmental bulletin paper
  • ISSN
    0001-6055
  • Data Source
    IR  J-STAGE 
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