Folic acid polyglutamylation triggers MAP2K5 signaling to induce adipocyte lipid catabolism
- 1University of Wisconsin-Madison
Abstract
Adipocyte signaling adaptively responds to macronutrients, but how essential micronutrients impact lipid homeostasis remains poorly understood. Here, we demonstrate that folate polyglutamylation, the sequential conjugation of glutamate residues to folate, serves as a dynamic biochemical process regulating metabolic signaling. Using our folate metabolomics platform, we show that polyglutamylated folic acid accumulates in healthy adipose tissue, but is depleted in obesity across mice and humans, independent of circulating folate levels. Genetic ablation of the polyglutamylation enzyme folylpolyglutamate synthase (Fpgs) in adipocytes suppresses lipid catabolism to induce cell-autonomous lipid accumulation, operating independently of canonical adipogenesis or downstream one-carbon flux. Target-engagement proteomics identifies monoglutamylated folic acid as a Map2k5-interacting molecule that inhibits Map2k5 activity, whereas Fpgs-mediated folic acid polyglutamylation acts as a chemical switch that disrupts this interaction to promote lipolysis. In vivo, whole-body inhibition of Map2k5 or adipose-targeted genetic depletion of Fpgs increases body fat mass in the absence of dietary obesogenic triggers. Furthermore, single-cell and single-nuclear transcriptomic analyses establish the Fpgs-Map2k5 pathway as a core transcriptional signature of mouse and human adipose tissues. These findings uncover a non-canonical signaling role for folate that regulates adipocyte lipid homeostasis.
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BibTeX
@misc{kim2026folic,
title = {{Folic acid polyglutamylation triggers MAP2K5 signaling to induce adipocyte lipid catabolism}},
author = {W. S. Kim and R. Danner and J. Cho and J. Williams and L. Lopez and Y. Bao and J. K. Hansen and E. M. Poad and H. Khan and D. Kim and B. W. Parks and J. G. Van Vraken and D. A. Harris and A. Galmozzi and M. E. Patti and S. N. Chaudhari},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.15.751849},
url = {https://www.biorxiv.org/content/10.64898/2026.09.15.751849v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Folic acid polyglutamylation triggers MAP2K5 signaling to induce adipocyte lipid catabolism
AU - W. S. Kim
AU - R. Danner
AU - J. Cho
AU - J. Williams
AU - L. Lopez
AU - Y. Bao
AU - J. K. Hansen
AU - E. M. Poad
AU - H. Khan
AU - D. Kim
AU - B. W. Parks
AU - J. G. Van Vraken
AU - D. A. Harris
AU - A. Galmozzi
AU - M. E. Patti
AU - S. N. Chaudhari
PY - 2026
DA - 2026/09/15
PB - bioRxiv
DO - 10.64898/2026.09.15.751849
UR - https://www.biorxiv.org/content/10.64898/2026.09.15.751849v1
AB - Adipocyte signaling adaptively responds to macronutrients, but how essential micronutrients impact lipid homeostasis remains poorly understood. Here, we demonstrate that folate polyglutamylation, the sequential conjugation of glutamate residues to folate, serves as a dynamic biochemical process regulating metabolic signaling. Using our folate metabolomics platform, we show that polyglutamylated folic acid accumulates in healthy adipose tissue, but is depleted in obesity across mice and humans, independent of circulating folate levels. Genetic ablation of the polyglutamylation enzyme folylpolyglutamate synthase (Fpgs) in adipocytes suppresses lipid catabolism to induce cell-autonomous lipid accumulation, operating independently of canonical adipogenesis or downstream one-carbon flux. Target-engagement proteomics identifies monoglutamylated folic acid as a Map2k5-interacting molecule that inhibits Map2k5 activity, whereas Fpgs-mediated folic acid polyglutamylation acts as a chemical switch that disrupts this interaction to promote lipolysis. In vivo, whole-body inhibition of Map2k5 or adipose-targeted genetic depletion of Fpgs increases body fat mass in the absence of dietary obesogenic triggers. Furthermore, single-cell and single-nuclear transcriptomic analyses establish the Fpgs-Map2k5 pathway as a core transcriptional signature of mouse and human adipose tissues. These findings uncover a non-canonical signaling role for folate that regulates adipocyte lipid homeostasis.
ER -