SHARPIN-mediated regulation of protein arginine methyltransferase 5 controls melanoma growth
Hironari Tamiya, … , Kazuhiro Iwai, Ze’ev A. Ronai
Hironari Tamiya, … , Kazuhiro Iwai, Ze’ev A. Ronai
Published December 11, 2017
Citation Information: J Clin Invest. 2018;128(1):517-530. https://doi.org/10.1172/JCI95410.
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Research Article Cell biology Oncology

SHARPIN-mediated regulation of protein arginine methyltransferase 5 controls melanoma growth

Abstract

SHARPIN, an adaptor for the linear ubiquitin chain assembly complex (LUBAC), plays important roles in NF-κB signaling and inflammation. Here, we have demonstrated a LUBAC-independent role for SHARPIN in regulating melanoma growth. We observed that SHARPIN interacted with PRMT5, a type II protein arginine methyltransferase, and increased its multiprotein complex and methyltransferase activity. Activated PRMT5 controlled the expression of the transcription factors SOX10 and MITF by SHARPIN-dependent arginine dimethylation and inhibition of the transcriptional corepressor SKI. Activation of PRMT5 by SHARPIN counteracted PRMT5 inhibition by methylthioadenosine, a substrate of methylthioadenosine phosphorylase, which is codeleted with cyclin-dependent kinase inhibitor 2A (CDKN2A) in approximately 15% of human cancers. Collectively, we identified a LUBAC-independent role for SHARPIN in enhancing PRMT5 activity that contributes to melanomagenesis through the SKI/SOX10 regulatory axis.

Authors

Hironari Tamiya, Hyungsoo Kim, Oleksiy Klymenko, Heejung Kim, Yongmei Feng, Tongwu Zhang, Jee Yun Han, Ayako Murao, Scott J. Snipas, Lucia Jilaveanu, Kevin Brown, Harriet Kluger, Hao Zhang, Kazuhiro Iwai, Ze’ev A. Ronai

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Figure 6

SHARPIN regulation of PRMT5 activity controls SOX10 expression and growth in MTAP-deleted human melanomas.

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SHARPIN regulation of PRMT5 activity controls SOX10 expression and growt...
(A) Expression of MTAP and CDKN2A genes in melanoma patients (TCGA, n = 472). Green and red vertical lines indicate the cutoffs for classification as low-MTAP (n = 70) and high-MTAP (n = 50) melanomas, respectively. The green horizontal line indicates the expression level in normal tissue (TCGA, n = 1). (B) Pearson’s correlation coefficients for SHARPIN and SOX10 or SHARPIN and PAX3 expression in all (n = 472, blue), MTAP-low (n = 70, green), and MTAP-high (n = 50, red) melanoma samples. (C) Immunoblot analysis of the indicated proteins in melanoma cells with high, medium, or low sensitivity to growth inhibition by SHARPIN KD. (D) Immunoblot analysis (left upper) and colony-forming efficiency (lower) assay of WM35 cells expressing empty vector (control) or overexpressing SHARPIN. Cells were treated with vehicle (DMSO) or MTA (100 μM) for 72 hours. For CFE, cells were seeded at 103/well and colonies were visualized and quantified (lower right) after 14 days in culture. PRMT5 activity (upper right) was assessed in anti-PRMT5–immunoprecipitated cell lysates. The quantitation data are presented as mean ± SD. n = 3 (lower right). n = 6 (upper right). Statistical significance was calculated using 2-way ANOVA (Tukey’s test). *P < 0.05; ***P < 0.0005. (C and D) Data shown represent at least 2 independent experiments.