Absence of Complex I Implicates Rearrangement of the Respiratory Chain in European Mistletoe

authored by

Jennifer Senkler, Nils Rugen, Holger Eubel, Jan Hegermann, Hans Peter Braun

Abstract

The mitochondrial oxidative phosphorylation (OXPHOS) system, which is based on the presence of five protein complexes, is in the very center of cellular ATP production. Complexes I to IV are components of the respiratory electron transport chain that drives proton translocation across the inner mitochondrial membrane. The resulting proton gradient is used by complex V (the ATP synthase complex) for the phosphorylation of ADP. Occurrence of complexes I to V is highly conserved in eukaryotes, with exceptions being restricted to unicellular parasites that take up energy-rich compounds from their hosts. Here we present biochemical evidence that the European mistletoe (Viscum album), an obligate semi-parasite living on branches of trees, has a highly unusual OXPHOS system. V. album mitochondria completely lack complex I and have greatly reduced amounts of complexes II and V. At the same time, the complexes III and IV form remarkably stable respiratory supercomplexes. Furthermore, complexome profiling revealed the presence of 150 kDa complexes that include type II NAD(P)H dehydrogenases and an alternative oxidase. Although the absence of complex I genes in mitochondrial genomes of mistletoe species has recently been reported, this is the first biochemical proof that these genes have not been transferred to the nuclear genome and that this respiratory complex indeed is not assembled. As a consequence, the whole respiratory chain is remodeled. Our results demonstrate that, in the context of parasitism, multicellular life can cope with lack of one of the OXPHOS complexes and give new insights into the life strategy of mistletoe species.

Organisation(s)

Section Plant Molecular Biology and Plant Proteomics
Institute of Plant Genetics

External Organisation(s)

Hannover Medical School (MHH)

Type

Article

Journal

Current biology

Volume

28

Pages

1606-1613.e4

ISSN

0960-9822

Publication date

21.05.2018

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Agricultural and Biological Sciences(all), Biochemistry, Genetics and Molecular Biology(all)

Sustainable Development Goals

SDG 15 - Life on Land

Electronic version(s)

https://doi.org/10.1016/j.cub.2018.03.050 (Access: Open)