Naturally occurring cancer-associated mutations disrupt oligomerization and activity of protein arginine...

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Protein arginine methylation is a key posttranslational modification regulated by protein arginine methyltransferase (PRMT) enzymes.
• Dysregulation of protein arginine methylation is implicated in various human diseases, including cancer.
• PRMT1, the primary PRMT isoform, plays vital roles in transcription, DNA repair, apoptosis, and cell proliferation.

Purpose of the Study:

• To identify inactivating mutations in the PRMT1 dimerization arm using the Catalogue of Somatic Mutations in Cancer (COSMIC) database.
• To investigate the functional impact of identified mutations on PRMT1 dimer formation, S-adenosyl-L-methionine (AdoMet) binding, and methyltransferase activity.

Main Methods:

• Database search (COSMIC) for PRMT1 mutations.
• Site-directed mutagenesis to introduce specific mutations.
• Analytical ultracentrifugation and native PAGE to assess protein oligomerization.
• Enzyme activity assays to measure methyltransferase function.
• Molecular dynamics simulations to elucidate structural mechanisms.

Main Results:

• Three specific mutations (W215L, Y220N, M224V in human PRMT1V2) were identified in the PRMT1 dimerization arm.
• These mutations significantly disrupted PRMT1 oligomer formation.
• Impaired S-adenosyl-L-methionine (AdoMet) binding and reduced methyltransferase activity were observed.
• Molecular dynamics simulations indicated that mutations alter dimerization arm conformation, hindering dimer formation.

Conclusions:

• Identified PRMT1 mutations disrupt dimerization, leading to impaired arginine methylation.
• These findings provide a molecular rationale for the link between PRMT1 dysregulation and disease.
• Understanding these mutations' effects is crucial for comprehending cellular health consequences.