Methenyltetrahydrofolate synthetase is a high-affinity catecholamine-binding protein

Area of Science:

• Biochemistry
• Cell Biology
• Metabolic Pathways

Background:

• 5,10-methenyltetrahydrofolate synthetase (MTHFS) is crucial for one-carbon metabolism.
• The interaction of MTHFS with other cellular components is not fully understood.

Purpose of the Study:

• To investigate the nature of a chromophore co-purifying with recombinant mouse MTHFS.
• To determine the functional implications of the interaction between MTHFS and catecholamines in folate metabolism.

Main Methods:

• Recombinant protein expression and purification (Escherichia coli).
• Spectroscopic analysis (UV-Vis absorption, mass spectrometry) for chromophore identification.
• Enzyme binding assays with purified MTHFS proteins.
• Cell culture experiments (MCF-7 cells) to assess folate turnover and accumulation.

Main Results:

• A chromophore, identified as oxidized N-acetyldopamine (NADA), was found to co-purify with MTHFS.
• NADA binds tightly to both mouse and rabbit liver MTHFS.
• NADA addition to MCF-7 cells accelerated folate turnover and decreased cellular folate levels.
• Overexpression of MTHFS in MCF-7 cells altered NADA's effect on folate depletion.

Conclusions:

• This study establishes a novel link between catecholamines and one-carbon metabolism.
• Oxidized N-acetyldopamine (NADA) directly impacts MTHFS activity and folate homeostasis.
• NADA accelerates folate turnover and impairs cellular folate accumulation, suggesting a regulatory role in folate metabolism.