Subunit composition of mitochondrial dehydrogenase complexes in diplonemid flagellates

0575407 - BC 2024 RIV NL eng J - Journal Article
Záhonová, Kristýna - Valach, M. - Tripathi, Pragya - Benz, Corinna - Opperdoes, F. R. - Baráth, P. - Lukáčová, V. - Danchenko, M. - Faktorová, Drahomíra - Horváth, A. - Burger, G. - Lukeš, Julius - Škodová-Sveráková, Ingrid
Subunit composition of mitochondrial dehydrogenase complexes in diplonemid flagellates.
Biochimica et Biophysica Acta-General Subjects. Roč. 1867, č. 9 (2023), č. článku 130419. ISSN 0304-4165. E-ISSN 1872-8006
R&D Projects: GA ČR(CZ) GX23-06479X; GA MŠMT(CZ) EF16_019/0000759
Grant - others:Gordon and Betty Moore Foundation(US) #9354
Program: Science
Institutional support: RVO:60077344
Keywords : Dehydrogenase complexes * Evolution * Diplonema papillatum * Diplonemids * Protist * Mitochondrion
OECD category: Cell biology
Impact factor: 3, year: 2022
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S0304416523001174?via%3Dihub

In eukaryotes, pyruvate, a key metabolite produced by glycolysis, is converted by a tripartite mitochondrial pyruvate dehydrogenase (PDH) complex to acetyl-coenzyme A, which is fed into the tricarboxylic acid cycle. Two additional enzyme complexes with analogous composition catalyze similar oxidative decarboxylation reactions albeit using different substrates, the branched-chain ketoacid dehydrogenase (BCKDH) complex and the 2-oxo-glutarate dehydrogenase (OGDH) complex. Comparative transcriptome analyses of diplonemids, one of the most abundant and diverse groups of oceanic protists, indicate that the conventional E1, E2, and E3 subunits of the PDH complex are lacking. E1 was apparently replaced in the euglenozoan ancestor of diplonemids by an AceE protein of archaeal type, a substitution that we also document in dinoflagellates. Here, we demonstrate that the mitochondrion of the model diplonemid Paradiplonema papillatum displays pyruvate and 2-oxoglutarate dehy-drogenase activities. Protein mass spectrometry of mitochondria reveal that the AceE protein is as abundant as the E1 subunit of BCKDH. This corroborates the view that the AceE subunit is a functional component of the PDH complex. We hypothesize that by acquiring AceE, the diplonemid ancestor not only lost the eukaryotic-type E1, but also the E2 and E3 subunits of the PDH complex, which are present in other euglenozoans. We posit that the PDH activity in diplonemids seems to be carried out by a complex, in which the AceE protein partners with the E2 and E3 subunits from BCKDH and/or OGDH.
Permanent Link: https://hdl.handle.net/11104/0345272