BMSE Seminar:"Arginine Methylation – Substrates, Effectors & Crosstalk"

Speaker

Prof. Mark T. Bedford (MD Andersen), Host: Norbert Reich
MD Andersen

Date and Location

Wednesday January 16, 2019 11:00am to 12:00pm
1601 Elings Hall

Abstract

The coactivator-associated arginine methyltransferase (CARM1) functions as a regulator of transcription and splicing by methylating a diverse array of substrates. CARM1 is one of nine members of the protein arginine methyltransferase (PRMT) family.  In order to broaden our understanding of CARM1’s mechanistic actions, we sought to identify additional substrates for this enzyme. To do this, we generated CARM1 substrate motif antibodies, and used immunoprecipitation coupled with mass spectrometry to identify novel cellular targets of CARM1, including Mediator Complex Subunit 12 (MED12) and the lysine methyltransferase KMT2D. Both of these proteins are implicated in enhancer function. We identified the primary CARM1-mediated MED12 methylation site as arginine 1899 (R1899). We are currently investigating the biological roles of this methylation, and we have preliminary data indicating that Mediator methylation regulates its ability to bind RNA.

We are also interested in identifying the “readers” of the methyl-motifs. We have generated a protein domain microarray approach to do this, and I will introduce this screening platform. Finally, a number of specific small molecule inhibitors have been developed to target the different PRMTs. We are using these compounds, in conjunction with CRISPR screening strategies, to characterize PRMT signaling pathways.

The coactivator-associated arginine methyltransferase (CARM1) functions as a regulator of transcription and splicing by methylating a diverse array of substrates. CARM1 is one of nine members of the protein arginine methyltransferase (PRMT) family.  In order to broaden our understanding of CARM1’s mechanistic actions, we sought to identify additional substrates for this enzyme. To do this, we generated CARM1 substrate motif antibodies, and used immunoprecipitation coupled with mass spectrometry to identify novel cellular targets of CARM1, including Mediator Complex Subunit 12 (MED12) and the lysine methyltransferase KMT2D. Both of these proteins are implicated in enhancer function. We identified the primary CARM1-mediated MED12 methylation site as arginine 1899 (R1899). We are currently investigating the biological roles of this methylation, and we have preliminary data indicating that Mediator methylation regulates its ability to bind RNA.

We are also interested in identifying the “readers” of the methyl-motifs. We have generated a protein domain microarray approach to do this, and I will introduce this screening platform. Finally, a number of specific small molecule inhibitors have been developed to target the different PRMTs. We are using these compounds, in conjunction with CRISPR screening strategies, to characterize PRMT signaling pathways.