Probing the Cancer Mutational Landscape of KMT2 Regulatory Subunits

Area of Science:

• Epigenetics
• Molecular Biology
• Cancer Research

Background:

• Lysine MethylTransferase 2 (KMT2) family proteins are frequently altered in various cancers.
• Mutations often affect key functional regions of KMT2 regulatory subunits, including WDR5, RbBP5, ASH2L, and DPY-30.

Purpose of the Study:

• To systematically characterize cancer-associated mutations impacting the WDR5/RbBP5/ASH2L/DPY-30 (WRAD) complex formation.
• To investigate the functional consequences of these mutations on protein interactions and complex stability.

Main Methods:

• Binding assays to assess protein-protein interactions.
• Thermal stability assays to evaluate complex integrity.
• Systematic mutational analysis of key residues within the WRAD complex.

Main Results:

• Several cancer mutations did not disrupt ASH2L binding to DPY-30 or RbBP5.
• Identified gain-of-function ASH2L mutants influencing RbBP5 binding through long-range interactions.
• Discovered RbBP5 mutations weakening WDR5 interactions and defined the optimal WDR5-binding motif.

Conclusions:

• Cancer-associated mutations can lead to gain-of-function in ASH2L, impacting epigenetic regulation.
• Understanding these mutations provides a basis for developing novel therapeutic strategies targeting the WRAD complex.
• Defined the WDR5-binding motif of RbBP5, aiding in the design of targeted therapies.