Quantitative Methods to Study Protein Arginine Methyltransferase 1-9 Activity in Cells

Area of Science:

• Biochemistry
• Molecular Biology
• Epigenetics

Background:

• Protein methyltransferases (PRMTs) are enzymes that modify arginine residues on proteins.
• Nine PRMT family members exist, catalyzing distinct arginine methylation patterns (monomethylation, symmetric/asymmetric dimethylation).
• Existing antibodies for detecting arginine methylation offer tools but face challenges in specificity due to overlapping substrates.

Purpose of the Study:

• To develop and validate robust cellular assays for quantifying the enzymatic activity of individual PRMT family members.
• To address challenges in PRMT antibody-based assay development, including substrate overlap and antibody specificity.
• To provide protocols for straightforward measurement of PRMT activity in cellular contexts.

Main Methods:

• Designed a panel of PRMT activity assays using carefully selected representative substrates for eight PRMTs.
• Validated substrate specificity and antibody reliability through knockdown and overexpression experiments.
• Utilized fluorescent western blot techniques for quantitative measurement in cell culture.

Main Results:

• Developed and validated protocols for cellular assays measuring individual PRMT enzymatic activity.
• Demonstrated straightforward assay performance suitable for standard cell culture and western blot laboratories.
• Provided comprehensive guidelines for assay biomarkers, antibodies, and PRMT inhibitor compounds.

Conclusions:

• The developed cellular assays offer a reliable and accessible method for studying individual PRMT activities.
• These assays facilitate the development of PRMT activity biomarker assays, crucial for understanding their roles in health and disease.
• The study provides a valuable resource for researchers investigating PRMT function and exploring therapeutic strategies.