Title: Mitochondrial fusion supports increased oxidative phosphorylation during cell proliferation.

Authors: Yao, Cong-Hui; Wang, Rencheng; Wang, Yahui; Kung, Che-Pei; Weber, Jason D; Patti, Gary J

Published In Elife, (2019 01 29)

Abstract: Proliferating cells often have increased glucose consumption and lactate excretion relative to the same cells in the quiescent state, a phenomenon known as the Warburg effect. Despite an increase in glycolysis, however, here we show that non-transformed mouse fibroblasts also increase oxidative phosphorylation (OXPHOS) by nearly two-fold and mitochondrial coupling efficiency by ~30% during proliferation. Both increases are supported by mitochondrial fusion. Impairing mitochondrial fusion by knocking down mitofusion-2 (Mfn2) was sufficient to attenuate proliferation, while overexpressing Mfn2 increased proliferation. Interestingly, impairing mitochondrial fusion decreased OXPHOS but did not deplete ATP levels. Instead, inhibition caused cells to transition from excreting aspartate to consuming it. Transforming fibroblasts with the Ras oncogene induced mitochondrial biogenesis, which further elevated OXPHOS. Notably, transformed fibroblasts continued to have elongated mitochondria and their proliferation remained sensitive to inhibition of Mfn2. Our results suggest that cell proliferation requires increased OXPHOS as supported by mitochondrial fusion.

PubMed ID: 30694178

MeSH Terms: 3T3-L1 Cells; Adenosine Triphosphate/biosynthesis; Animals; Aspartic Acid/metabolism; Biological Transport; Cell Proliferation/genetics*; GTP Phosphohydrolases/genetics*; GTP Phosphohydrolases/metabolism; Gene Expression Regulation; Genes, ras; Glycolysis/genetics; HeLa Cells; Humans; MCF-7 Cells; Mice; Mitochondria/genetics*; Mitochondria/metabolism; Mitochondrial Dynamics/genetics*; Organelle Biogenesis; Oxidative Phosphorylation*; Oxygen Consumption/genetics; Transfection; Transgenes