Mitochondrial oxidative phosphorylation complexes exist in the sarcolemma of skeletal muscle

Abstract

Although proteomic analyses have revealed the presence of mitochondrial oxidative phosphorylation (OXPHOS) proteins in the plasma membrane, there have been no in-depth evaluations of the presence or function of OXPHOS I-V in the plasma membrane. Here, we demonstrate the in situ localization of OXPHOS I-V complexes to the sarcolemma of skeletal muscle by immunofluorescence and immunohistochemistry. A portion of the OXPHOS I-V complex proteins was not co-stained with MitoTracker but co-localized with caveolin-3 in the sarcolemma of mouse gastrocnemius. Mitochondrial matrix-facing OXPHOS complex subunits were ectopically expressed in the sarcolemma of the non-permeabilized muscle fibers and C2C12 myotubes. The sarcolemmal localization of cytochrome c was also observed from mouse gastrocnemius muscles and C2C12 myotubes, as determined by confocal and total internal resonance fluorescence (TIRF) microscopy. Based on these data, we conclude that a portion of OXPHOS complexes is localized in the sarcolemma of skeletal muscle and may have non-canonical functions. [BMB Reports 2016; 49(2): 116-121]

Caveolin‐1 deficiency induces premature senescence with mitochondrial dysfunction

“…The mitochondrial OCR and ECAR were analyzed using an XF24 Extracellular Flux Analyzer (Seahorse Bioscience, Santa Clara, CA, USA) as described previously (Lee et al ., ).…”

An MG53-IRS1-interaction disruptor ameliorates insulin resistance

“…The HEK 293 cell line and C2C12 myoblasts were maintained as previously described 22 . Briefly, HEK 293 cells and C2C12 myoblasts were grown in DMEM supplemented with 1% penicillin/streptomycin and 10% fetal bovine serum in a 5% CO 2 incubator at 37°C.…”

Chemiosmotic coupling in oxidative phosphorylation: The history of a hard experimental effort hampered by the Heisenberg indeterminacy principle

“…The Chemiosmotic Theory (Mitchell, 1961) as it was formulated is a process that can only take place in organelle possessing double membrane systems forming closed compartments to entrap protons, such as mitochondrial cristae, bacteria and thylakoids. Here, for the sake of simplicity, we have considered the mitochondrial inner membrane, even though in recent years, it has been shown that the oxidative phosphorylation (OXPHOS), coupled to aerobic ATP synthesis, also occurs in extra-mitochondrial districts, as rod outer segment (OS ) disks (Calzia et al, 2014) (Calzia et al, 2013) (Bianchini et al, 2008) (Panfoli et al, 2009), myelin sheath (Ravera et al, 2009) (Ravera et al, 2011b) (Morelli et al, 2011) (Ravera et al, 2015), plasma membrane (Mangiullo et al, 2008) (Arakaki et al, 2003) (Arakaki et al, 2007 (Adriano et al, 2011) (Chang et al, 2012) (Lee et al, 2016) (Taurino & Gnoni, 2018) (Taurino et al, 2016) (Gao et al, 2017) extracellular vesicles shedding form cells, such as exosomes and microvesicles, which seem to carry an unsuspected metabolic signature (Panfoli et al, 2016). In particular, recent data indicate an active extramitochondrial OXPHOS in the endoplasmic reticulum of platelets which both have elevated ATP need but possess very little mitochondria (Ravera et al, 2018).…”

“…In fact, it was demonstrated that many biological membranes, devoid of closed compartments and of mitochondria, conduct OXPHOS with high efficiency (Calzia et al, 2010) (Roehlecke et al, 2013) (Mangiullo et al, 2008) (Panfoli et al, 2012) (Ravera et al, 2011b) (Ravera et al, 2013) (Ravera et al, 2018) , challenging the idea that it is exclusive of mitochondria, thylakoid and bacteria. Of particular interest are the reports of the ability of plasma membranes to synthesize ATP outside the cell, as they harbour the five complexes of respiration (Mangiullo et al, 2008) (Arakaki et al, 2003) (Arakaki et al, 2007) (Adriano et al, 2011) (Chang et al, 2012) (Lee et al, 2016).…”