Pathogenic mutations in NUBPL affect complex I activity and cold tolerance in the yeast model Yarrowia lipolytica

MacLean, A. E., Kimonis, V. E. and Balk, J. (2018) Pathogenic mutations in NUBPL affect complex I activity and cold tolerance in the yeast model Yarrowia lipolytica. Human Molecular Genetics, 27(21), pp. 3697-3709. (doi: 10.1093/hmg/ddy247) (PMID:29982452) (PMCID:PMC6196649)

Abstract

Complex I deficiency is a common cause of mitochondrial disease, resulting from mutations in genes encoding structural subunits, assembly factors or defects in mitochondrial gene expression. Advances in genetic diagnostics and sequencing have led to identification of several variants in NUBPL (nucleotide binding protein-like), encoding an assembly factor of complex I, which are potentially pathogenic. To help assign pathogenicity and learn more about the function of NUBPL, amino acid substitutions were recreated in the homologous Ind1 protein of the yeast model Yarrowia lipolytica. Leu102Pro destabilized the Ind1 protein, leading to a null-mutant phenotype. Asp103Tyr, Leu191Phe and Gly285Cys affected complex I assembly to varying degrees, whereas Gly136Asp substitution in Ind1 did not impact on complex I levels nor dNADH:ubiquinone activity. Blue-native polyacrylamide gel electrophoresis and immunolabelling of the structural subunits NUBM and NUCM revealed that all Ind1 variants accumulated a Q module intermediate of complex I. In the Ind1 Asp103Tyr variant, the matrix arm intermediate was virtually absent, indicating a dominant effect. Dysfunction of Ind1, but not absence of complex I, rendered Y. lipolytica sensitive to cold. The Ind1 Gly285Cys variant was able to support complex I assembly at 28°C, but not at 10°C. Our results indicate that Ind1 is required for progression of assembly from the Q module to the full matrix arm. Cold sensitivity could be developed as a phenotype assay to demonstrate pathogenicity of NUBPL mutations and other complex I defects.

• Item Type: Articles
• Additional Information: Funding: John Innes Foundation (studentship to A.E.M.); the Spooner Girls Foundation, the UC Irvine Institute for Clinical and Translational Science, and the Center for Autism Research (to V.E.K.); and the Biotechnology and Biological Sciences Research Council (BBSRC) (BB/J004561/1 to J.B.)
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: MacLean, Dr Andrew
• Authors: MacLean, A. E., Kimonis, V. E., and Balk, J.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Human Molecular Genetics
• Publisher: Oxford University Press
• ISSN: 0964-6906
• ISSN (Online): 1460-2083
• Published Online: 04 July 2018
• Copyright Holders: Copyright © The Authors 2018
• First Published: First published in Human Molecular Genetics 27(21):3697-3709
• Publisher Policy: Reproduced under a Creative Commons license