bims-resufa 2026-09-06 papers

on Respiratory supercomplex factors

Issue of 2026–09–06
two papers selected by
Gavin McStay, Liverpool John Moores University

BN-PAGE of Ustilago maydis Respiratory Complexes.
Cardiolipin deficiency disrupts electron transport chain and drives steatohepatitis.

Methods Mol Biol. 2026 ;3050 463-473

BN-PAGE of Ustilago maydis Respiratory Complexes.

Lucero Romero-Aguilar, Guadalupe Guerra Sánchez, Héctor Vázquez Meza, Juan Pablo Pardo.

  Isolated mitochondria are valuable for the study of the respiratory chain, protein complex assembly, and the activities of the Krebs cycle enzymes, among others. Here, we present a protocol for the isolation of functional U. maydis mitochondria, which involves mechanically disrupting the cell wall with glass beads and performing two centrifugations. The first step is carried out at low speed to remove intact cells and cell debris, followed by a high-speed centrifugation to obtain mitochondria. For the separation of respiratory complexes and supercomplexes, we describe the solubilization of protein complexes from mitochondria with digitonin and their separation by blue native polyacrylamide gel electrophoresis (BN-PAGE), followed by the in-gel activity of respiratory complexes.

Keywords:  Basidiomycete; Blue native PAGE; Mitochondria isolation; Respiratory complexes

DOI:  https://doi.org/10.1007/978-1-0716-5364-7_40
Elife. 2026 Sep 02. pii: RP106976. [Epub ahead of print]14

Cardiolipin deficiency disrupts electron transport chain and drives steatohepatitis.

Marisa J Brothwell, Guoshen Cao, J Alan Maschek, Annelise M Poss, Alek D Peterlin, Liping Wang, Talia B Baker, Justin L Shahtout, Piyarat Siripoksup, Quentinn J Pearce, Jordan M Johnson, Fabian M Finger, Alexandre Prola, Sarah A Pellizzari, Gillian L Hale, Allison M Manuel, Shinya Watanabe, Edwin R Miranda, Kajsa E Affolter, Trevor S Tippetts, Linda S Nikolova, Ran Hee Choi, Stephen T Decker, Mallikarjun Patil, J Leon Catrow, William L Holland, Sara M Nowinski, Daniel S Lark, Kelsey H Fisher-Wellman, Patrice N Mimche, Kimberley Evason, James E Cox, Scott A Summers, Zach Gerhart-Hines, Katsuhiko Funai.

  Metabolic dysfunction-associated steatotic liver disease (MASLD) is a progressive disorder marked by lipid accumulation, leading to metabolic dysfunction-associated steatohepatitis (MASH). A key feature of the transition to MASH involves oxidative stress resulting from defects in mitochondrial oxidative phosphorylation (OXPHOS). Here, we show that pathological alterations in the lipid composition of the inner mitochondrial membrane (IMM) directly instigate electron transfer inefficiency to promote oxidative stress. Specifically, mitochondrial cardiolipin (CL) was downregulated with MASLD/MASH in humans and in mice. Hepatocyte-specific CL synthase knockout (CLS-LKO) led to spontaneous and robust MASH with extensive steatotic and fibrotic phenotype. Loss of CL paradoxically increased mitochondrial respiratory capacity but also promoted electron leak primarily at sites IIIQO and IIF of the electron transport chain (ETC), reduced the formation of I + III2 + IV respiratory supercomplex, and disrupted the propensity of coenzyme Q to become reduced. Thus, low mitochondrial CL disrupts the ETC to promote oxidative stress and contributes to the pathogenesis of MASH.

Keywords:  cardiolipin; cell biology; human; liver; mitochondria; mouse

DOI:  https://doi.org/10.7554/eLife.106976