Mitochondrial cristae narrowing upon higher 2-oxoglutarate load

Publication date: Available online 25 June 2019Source: Biochimica et Biophysica Acta (BBA) - BioenergeticsAuthor(s): Andrea Dlasková, Tomáš Špaček, Hana Engstová, Jitka Špačková, Adam Schröfel, Blanka Holendová, Katarína Smolková, Lydie Plecitá-Hlavatá, Petr JežekAbstractHypoxia causes mitochondrial cristae widening, enabled by the ~20% degradation of Mic60/mitofilin, with concomitant clustering of the MICOS complex, reflecting the widening of crista junctions (outlets) (Plecitá-Hlavatá et al. FASEB J., 2016 30:1941–1957). Attempting to accelerate metabolism by the addition of membrane-permeant dimethyl-2-oxoglutarate (dm2OG) to HepG2 cells pre-adapted to hypoxia, we found cristae narrowing by transmission electron microscopy. Glycolytic HepG2 cells, which downregulate hypoxic respiration, instantly increased respiration with dm2OG. Changes in intracristal space (ICS) morphology were also revealed by 3D super-resolution microscopy using Eos-conjugated ICS-located lactamase-β. Cristae topology was resolved in detail by focused-ion beam/scanning electron microscopy (FIB/SEM). The spatial relocations of key cristae-shaping proteins were indicated by immunocytochemical stochastic 3D super-resolution microscopy (dSTORM), while analyzing inter-antibody-distance histograms: i) ATP-synthase dimers exhibited a higher fraction of shorter inter-distances between bound F1-α primary Alexa-Fluor-647-conjugated antibodies, indicating cristae narrowing. ii) Mic60/mitofi...

Source: Biochimica et Biophysica Acta (BBA) Bioenergetics - June 25, 2019 Category: Biochemistry Source Type: research