ABHD11 maintains 2-oxoglutarate metabolism by preserving functional lipoylation of the 2-oxoglutarate dehydrogenase complex

Peter S J Bailey,Christian Frezza,Stephen P Burr,Ana S H Costa,Brian M Ortmann,Jack W Houghton,Robin Antrobus,Anthony W Martinelli,James A Nathan

doi:10.1038/s41467-020-17862-6

Abstract

2-oxoglutarate (2-OG or α-ketoglutarate) relates mitochondrial metabolism to cell function by modulating the activity of 2-OG dependent dioxygenases involved in the hypoxia response and DNA/histone modifications. However, metabolic pathways that regulate these oxygen and 2-OG sensitive enzymes remain poorly understood. Here, using CRISPR Cas9 genome-wide mutagenesis to screen for genetic determinants of 2-OG levels, we uncover a redox sensitive mitochondrial lipoylation pathway, dependent on the mitochondrial hydrolase ABHD11, that signals changes in mitochondrial 2-OG metabolism to 2-OG dependent dioxygenase function. ABHD11 loss or inhibition drives a rapid increase in 2-OG levels by impairing lipoylation of the 2-OG dehydrogenase complex (OGDHc)—the rate limiting step for mitochondrial 2-OG metabolism. Rather than facilitating lipoate conjugation, ABHD11 associates with the OGDHc and maintains catalytic activity of lipoyl domain by preventing the formation of lipoyl adducts, highlighting ABHD11 as a regulator of functional lipoylation and 2-OG metabolism.

Highlights

2-oxoglutarate (2-OG or α-ketoglutarate) relates mitochondrial metabolism to cell function by modulating the activity of 2-OG dependent dioxygenases involved in the hypoxia response and DNA/histone modifications
ABHD11 loss leads to the accumulation of 2-OG and formation of L-2-HG, which inhibits 2-OG dependent dioxygenases involved in the hypoxia inducible factor (HIF) response and DNA hydroxymethylation, to genetic disruption of the OG dehydrogenase complex (OGDHc)
To find genes involved in 2-OG metabolism we utilised the sensitivity of the HIF response to 2-OG availability, and carried out CRISPR/Cas[9] mutagenesis screens in human cells using a fluorescent HIF reporter we developed[4,15]

Summary

Introduction

2-oxoglutarate (2-OG or α-ketoglutarate) relates mitochondrial metabolism to cell function by modulating the activity of 2-OG dependent dioxygenases involved in the hypoxia response and DNA/histone modifications. The ability to sense and respond to nutrient abundance is a fundamental requirement for cell survival, and to achieve this, cells have evolved several strategies that link metabolic function to transcriptional adaptation One such strategy is the coupling of 2-oxoglutarate (2-OG) metabolism to gene transcription, whereby 2-OG, a key component of TCA cycle, can facilitate cell function by modulating the activity of 2-OG dependent dioxygenases involved in the hypoxia inducible factor (HIF) response, DNA methylation, and histone modifications[1]. ABHD11 loss leads to the accumulation of 2-OG and formation of L-2-HG, which inhibits 2-OG dependent dioxygenases involved in the HIF response and DNA hydroxymethylation, to genetic disruption of the OGDHc. ABHD11 associates with the OGDHc and is required for catalytic activity and TCA cycle function. These studies identify a key role for ABHD11 in 2-OG metabolism, and demonstrate that lipoylation provides a previously unappreciated mechanism for mediating an adaptive transcriptional response to changes in OGDHc function

Methods

Results

Conclusion