Guiding COMPASS: Dpy-30 Positions SET1/MLL Epigenetic Signaling

Area of Science:

• Structural Biology
• Epigenetics
• Molecular Mechanisms

Background:

• Histone H3 lysine 4 (H3K4) methylation is a critical epigenetic mark.
• COMPASS-like complexes regulate H3K4 methylation.
• The roles of Dpy-30 and Ash2L within these complexes are not fully understood.

Purpose of the Study:

• To determine the high-resolution crystal structure of human COMPASS-like components Dpy-30 and Ash2L.
• To identify the interaction surface between Dpy-30 and Ash2L.
• To elucidate the role of this interaction in H3K4 methylation and KMT2 enzyme regulation.

Main Methods:

• High-resolution trimeric crystal structure determination of Dpy-30 and Ash2L.
• Biochemical assays to assess H3K4 methylation activity.
• Analysis of allosteric regulation mechanisms in KMT2 enzymes.

Main Results:

• The 2:1 crystal structure of human Dpy-30:Ash2L was solved.
• An uncharacterized interaction surface between Dpy-30 and Ash2L was identified.
• This interaction is essential for competent H3K4 methylation.

Conclusions:

• The Dpy-30:Ash2L interaction is vital for the function of COMPASS-like complexes.
• Dpy-30 plays a key role in the allosteric regulation of KMT2 enzymes.
• Structural insights provide a basis for understanding epigenetic regulation by H3K4 methylation.