Phosphorylation at the N-Terminal in Hmt1 Enhances Dimerization by Exposing the Binding Surface

Area of Science:

• Biochemistry
• Molecular Biology
• Cellular Processes

Background:

• Arginine methylation, a key post-translational modification (PTM), regulates vital cellular functions like transcription and nuclear transport.
• Protein arginine methyltransferases (PRMTs) catalyze methylation, requiring homodimer formation for enzymatic activity.
• Dysregulated PRMT dimerization is linked to disease development, highlighting the importance of understanding its regulation.

Purpose of the Study:

• To elucidate the mechanism by which phosphorylation of the Hmt1 monomer's N-terminal region influences its dimerization.
• To investigate the conformational changes induced by phosphorylation using molecular dynamics (MD) simulations.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the Hmt1 monomer, incorporating phosphorylation.
• Analysis focused on the conformational dynamics of the N-terminal region and its interaction with the arm structure.

Main Results:

• Phosphorylation of Hmt1's N-terminal region reduces its interaction with the arm structure, crucial for homodimer formation.
• This leads to increased exposure of the homodimer binding surface.
• The conformational shift is attributed to the phosphate group's charge and hydrophilicity, and secondary structure formation.

Conclusions:

• Phosphorylation-induced conformational changes in Hmt1's N-terminus facilitate homodimerization.
• Understanding this mechanism provides insights into PRMT regulation and its implications in disease.
• This study clarifies a key step in arginine methylation regulation by PRMTs.