Related Experiment Video
Updated: Oct 25, 2025

Quantitative Methods to Study Protein Arginine Methyltransferase 1-9 Activity in Cells
Published on: August 7, 2021
Molecular basis for substrate recruitment to the PRMT5 methylosome
Kathleen M Mulvaney1, Christa Blomquist1, Nischal Acharya1
1Broad Institute, Cambridge, MA, USA.
Protein arginine methyltransferase 5 (PRMT5) uses a common binding motif on adaptor proteins to recruit substrates. Disrupting this interaction halts cancer cell growth, offering a therapeutic target for MTAP-null cancers.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Biology
Background:
- Protein arginine methyltransferase 5 (PRMT5) is a key enzyme and therapeutic target in MTAP-null cancers.
- The mechanism of PRMT5 substrate recruitment via adaptor proteins was previously unclear.
Purpose of the Study:
- To identify and characterize the mechanism of PRMT5 substrate adaptor interaction.
- To explore the therapeutic potential of targeting the PRMT5-adaptor interface in cancer.
Main Methods:
- Identification of a conserved peptide motif in PRMT5 adaptors (CLNS1A, RIOK1, COPR5).
- Structural resolution of the PRMT5-adaptor interface.
- Genetic perturbation studies to assess the functional impact of disrupting the interface.
Main Results:
- A conserved peptide sequence is necessary and sufficient for PRMT5 adaptor binding.
- PRMT5 utilizes modular adaptors with a common binding motif for substrate recruitment.
- Disruption of the interface impairs methylation of key substrates (spliceosome, histones, ribosomal complexes) and affects spliceosome activity, causing intron retention.
- Targeting this interface inhibits MTAP-null tumor cell growth.
Conclusions:
- PRMT5 employs a modular adaptor system for substrate recruitment via a conserved binding motif.
- The PRMT5-adaptor interface is crucial for cellular function and represents a viable therapeutic target for MTAP-null cancers.
Related Concept Videos
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Transfer RNA Synthesis
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Mitochondrial Precursor Proteins
Most of the mitochondrial...
Mitochondrial Protein Sorting
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Directing Proteins to the Rough Endoplasmic Reticulum

