The uncharacterized protein FAM47E interacts with PRMT5 and regulates its functions.

Baskar Chakrapani,Arunkumar Dhayalan,Arun Mahesh,Mohd Imran K Khan,Gayathri Govindaraju,Sharad Awasthi,Somlee Gupta,Mamta Verma,Rajashekar Varma Kadumuri,Sreenivas Chavali,Arumugam Rajavelu

doi:10.26508/lsa.202000699

Abstract

Protein arginine methyltransferase 5 (PRMT5) symmetrically dimethylates arginine residues in various proteins affecting diverse cellular processes such as transcriptional regulation, splicing, DNA repair, differentiation, and cell cycle. Elevated levels of PRMT5 are observed in several types of cancers and are associated with poor clinical outcomes, making PRMT5 an important diagnostic marker and/or therapeutic target for cancers. Here, using yeast two-hybrid screening, followed by immunoprecipitation and pull-down assays, we identify a previously uncharacterized protein, FAM47E, as an interaction partner of PRMT5. We report that FAM47E regulates steady-state levels of PRMT5 by affecting its stability through inhibition of its proteasomal degradation. Importantly, FAM47E enhances the chromatin association and histone methylation activity of PRMT5. The PRMT5-FAM47E interaction affects the regulation of PRMT5 target genes expression and colony-forming capacity of the cells. Taken together, we identify FAM47E as a protein regulator of PRMT5, which promotes the functions of this versatile enzyme. These findings imply that disruption of PRMT5-FAM47E interaction by small molecules might be an alternative strategy to attenuate the oncogenic function(s) of PRMT5.

Highlights

Arginine methylation is a widely prevalent, important posttranslational modification affecting various cellular processes (Peng & Wong, 2017)
We validated Protein arginine methyltransferase 5 (PRMT5)–FAM47E interaction in Y2H assay by using full-length FAM47E isoform 2 with appropriate vector controls
We observed the expression of reporter genes in both low stringency media and high-stringency media only if the Y2H constructs of PRMT5 and FAM47E were cotransformed

Summary

Introduction

Arginine methylation is a widely prevalent, important posttranslational modification affecting various cellular processes (Peng & Wong, 2017). PRMT5 plays an important role in the regulation of gene expression, splicing, chromatin remodeling, cell differentiation, and development (Stopa et al, 2015). PRMT5 participates in epigenetic regulation of chromatin structure and gene expression by introducing symmetric dimethylation at arginine 3 of histone 4 (H4R3me2s), arginine 2 and 8 of histone 3 (H3R2me2s and H3R8me2s) and arginine 3 of histone 2A (H2AR3me2s) (Pollack et al, 1999; Branscombe et al, 2001; Pal et al, 2004; Ancelin et al, 2006; Migliori et al, 2012). Depletion of PRMT5 inhibits cell proliferation, clonogenic capacity of the cells, and improves the prognosis of cancer patients making PRMT5 an important target for cancer therapy (Pal et al, 2004; Scoumanne et al, 2009; Wei et al, 2012; Chung et al, 2013; Morettin et al, 2015; Yang et al, 2016; Banasavadi-Siddegowda et al, 2018; Saloura et al, 2018; Xiao et al, 2019)

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Conclusion