A highly responsive pyruvate sensor reveals pathway-regulatory role of the mitochondrial pyruvate carrier MPC

• Published in: eLife 2020-03, Vol.9
• Main Authors: Arce-Molina, Robinson, Cortés-Molina, Francisca, Sandoval, Pamela Y, Galaz, Alex, Alegría, Karin, Schirmeier, Stefanie, Barros, L Felipe, San Martín, Alejandro
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Anion Transport Proteins - genetics; Anion Transport Proteins - metabolism; Astrocytes; Biosensing Techniques; Carbon; Cell Biology; Cell Line; Chlorocebus aethiops; COS Cells; Cytology; Drosophila melanogaster; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; energy metabolism; Experiments; genetically-encoded sensor; Gluconeogenesis; HEK293 Cells; HeLa Cells; Humans; Larva - metabolism; Localization; Membrane fluidity; Membrane potential; Metabolism; Metabolites; Mice; Mitochondria; Mitochondria - metabolism; Mitochondrial Membrane Transport Proteins - genetics; Mitochondrial Membrane Transport Proteins - metabolism; Models, Biological; Monocarboxylic Acid Transporters - genetics; Monocarboxylic Acid Transporters - metabolism; Organelles; Permeability; Phosphorylation; Physiology; Proteins; pyruvate; Pyruvic acid; Pyruvic Acid - metabolism; Quantitation; Regeneration; Sensors; Tools and Resources; transport-stop protocol
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.53917

Mitochondria generate ATP and building blocks for cell growth and regeneration, using pyruvate as the main substrate. Here we introduce PyronicSF, a user-friendly GFP-based sensor of improved dynamic range that enables real-time subcellular quantitation of mitochondrial pyruvate transport, concentration and flux. We report that cultured mouse astrocytes maintain mitochondrial pyruvate in the low micromolar range, below cytosolic pyruvate, which means that the mitochondrial pyruvate carrier MPC is poised to exert ultrasensitive control on the balance between respiration and anaplerosis/gluconeogenesis. The functionality of the sensor in living tissue is demonstrated in the brain of larvae. Mitochondrial subpopulations are known to coexist within a given cell, which differ in their morphology, mobility, membrane potential, and vicinity to other organelles. The present tool can be used to investigate how mitochondrial diversity relates to metabolism, to study the role of MPC in disease, and to screen for small-molecule MPC modulators.