Edc3 function in yeast and mammals is modulated by interaction with NAD-related compounds

Area of Science:

• Molecular Biology
• Biochemistry
• Post-transcriptional Regulation

Background:

• mRNA translation and degradation are regulated by proteins involved in decapping and processing body (P-body) assembly.
• The conserved enhancer of mRNA decapping 3 (Edc3) protein plays a key role in promoting mRNA decapping and P-body formation.

Purpose of the Study:

• To investigate the interaction of human Edc3 with small molecules, specifically NAD(H).
• To determine the functional significance of Edc3's interaction with NAD-related molecules in vivo.

Main Methods:

• Crystal structure analysis of the human Edc3 YjeF_N domain to identify potential binding sites.
• Structure modeling of human Edc3 and related proteins to predict small molecule interactions.
• In vitro biochemical assays to demonstrate direct binding of human Edc3 to NADH and chemical modification of NAD by human and yeast Edc3.
• In vivo studies using mutant Edc3 proteins to assess effects on mRNA degradation and P-body composition.

Main Results:

• Human Edc3 directly binds to NADH.
• Both human and yeast Edc3 proteins chemically modify NAD in vitro.
• Mutations disrupting NAD-related molecule binding or hydrolysis in Edc3 affect mRNA degradation control and/or P-body composition in vivo.

Conclusions:

• The interaction of Edc3 with NAD-related molecules is crucial for its function in regulating mRNA translation and degradation.
• This interaction provides a mechanism to link cellular energy status (via NAD) to post-transcriptional gene control.
• This study presents a novel connection between metabolites, enzymes, and RNA regulation.