APC/C-CDH1-regulated IDH3β coordinates with the cell cycle to promote cell proliferation

Abstract

Metabolic activities are often accompanied by cell-cycle progression, yet known connections between these two processes remain limited. Here, we identified the isocitrate dehydrogenase 3β (IDH3β) as a novel substrate of anaphase-promoting complex/cyclosome (APC/C)-CDH1 and an important regulator of the cell cycle. In esophageal squamous cell carcinoma (ESCC), IDH3β was posttranslationally upregulated in late G1 phase, and overexpression of IDH3β accelerated G1-S transition, contributing to the promotion of cell proliferation in vitro and in vivo. α-Ketoglutarate (α-KG), a crucial metabolite in tricarboxylic acid (TCA) cycle, was dependent on IDH3β level and partially accounted for IDH3β-mediated cell growth. IDH3β expression increased PFKFB3 protein levels and enhanced glucose uptake, and high expression of IDH3β correlated with poor survival in patients with ESCC, suggesting a potential application of IDH3β in prognosis. Overall, our results highlight a new molecular connection between cell-cycle regulation and the TCA cycle in ESCC.