Mitochondrial NADP+ is essential for proline biosynthesis during cell growth

Diem H. Tran, Rushendhiran Kesavan, Halie Rion, Mona Hoseini Soflaee, Ashley Solmonson, Divya Bezwada, Hieu S. Vu, Feng Cai, John A. Phillips, Ralph J. DeBerardinis, Gerta Hoxhaj

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Nicotinamide adenine dinucleotide phosphate (NADP+) is vital to produce NADPH, a principal supplier of reducing power for biosynthesis of macromolecules and protection against oxidative stress. NADPH exists in separate pools, in both the cytosol and mitochondria; however, the cellular functions of mitochondrial NADPH are incompletely described. Here, we find that decreasing mitochondrial NADP(H) levels through depletion of NAD kinase 2 (NADK2), an enzyme responsible for production of mitochondrial NADP+, renders cells uniquely proline auxotrophic. Cells with NADK2 deletion fail to synthesize proline, due to mitochondrial NADPH deficiency. We uncover the requirement of mitochondrial NADPH and NADK2 activity for the generation of the pyrroline-5-carboxylate metabolite intermediate as the bottleneck step in the proline biosynthesis pathway. Notably, after NADK2 deletion, proline is required to support nucleotide and protein synthesis, making proline essential for the growth and proliferation of NADK2-deficient cells. Thus, we highlight proline auxotrophy in mammalian cells and discover that mitochondrial NADPH is essential to enable proline biosynthesis.

Original languageEnglish (US)
Pages (from-to)571-585
Number of pages15
JournalNature Metabolism
Volume3
Issue number4
DOIs
StatePublished - Apr 2021

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Cell Biology
  • Physiology (medical)

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