Fig. 4: Immunohistochemical images demonstrating some components of the Mitochondrial Lactate Oxidation Complex (mLOC) in cultured L6 muscle cells.

This complex involves the mitochondrial constituent cytochrome oxidase (COx), lactate-pyruvate transport protein (MCT1), lactate dehydrogenase (LDH), and other constituents. A Colocalization of MCT1 and the mitochondrial reticulum. MCT1 was detected at both sarcolemmal and intracellular domains (A-1). Using MitoTracker, the mitochondrial reticulum was extensively elaborated and detected at intracellular domains throughout L6 cells (A-2). When signals from probes for the lactate transporter (MCT1, green, A-1) and mitochondria (red, A-2) were merged, the superimposition of the signals (yellow) showed the colocalization of MCT1 and components of the mitochondrial reticulum, particularly at perinuclear cell domains (A-3). In Panel (B), lactate dehydrogenase (LDH) (B-1), and mitochondrial cytochrome oxidase (COx) (B-2) are imaged. The superimposition of signals for LDH (red, B-1) and COx (green, B-2) shows the colocalization of LDH in the mitochondrial reticulum (yellow) of cultured L6 rat muscle cells (D-3). Depth of field ~1 μm, scale bar = 10 μm. Reprinted from Hashimoto et al.¹⁵³.