Dual-process brain mitochondria isolation preserves function and clarifies protein composition
| Autor: | Kalyani Chaubey, Kristi Lin-Rahardja, Andrew A. Pieper, Eric B. Taylor, Maria F. Noterman, Anjali M. Rajadhyaksha |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Calcium Channels L-Type solute carrier Protein subunit channel Mitochondrion Endoplasmic Reticulum Mice Animals Homeostasis Humans Mice Knockout Ion Transport Multidisciplinary biology Chemistry Endoplasmic reticulum Brain Membrane Proteins Biological Sciences Protein subcellular localization prediction Mitochondria Solute carrier family Cell biology Monocarboxylate transporter 1 Membrane protein neuropsychiatric disease transporter biology.protein Calcium Female Density gradient ultracentrifugation Neuroscience |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.2019046118 |
| Popis: | Significance The unique aspects of brain mitochondria composition and function are incompletely understood, and new approaches are required to understand their relationship. We addressed this challenge through a dual-process isolation procedure that yields both semipure brain mitochondria suitable for functional studies but not protein localization and ultrapure brain mitochondria that are suitable for determining protein localization but functionally compromised. We observed that contrary to the published literature, N-methyl-D-aspartate receptor, ryanodine receptor 1, glyceraldehyde 3-phosphate dehydrogenase, monocarboxylate transporter 1, excitatory amino acid transporter 1, and the L-type calcium channel Cav1.2α1 subunit are absent from brain mitochondria. Utilization of this dual-process brain mitochondria isolation technique will foster clarity on mechanisms of brain health and disease. The brain requires continuously high energy production to maintain ion gradients and normal function. Mitochondria critically undergird brain energetics, and mitochondrial abnormalities feature prominently in neuropsychiatric disease. However, many unique aspects of brain mitochondria composition and function are poorly understood. Developing improved neuroprotective therapeutics thus requires more comprehensively understanding brain mitochondria, including accurately delineating protein composition and channel–transporter functional networks. However, obtaining pure mitochondria from the brain is especially challenging due to its distinctive lipid and cell structure properties. As a result, conflicting reports on protein localization to brain mitochondria abound. Here we illustrate this problem with the neuropsychiatric disease-associated L-type calcium channel Cav1.2α1 subunit previously observed in crude mitochondria. We applied a dual-process approach to obtain functionally intact versus compositionally pure brain mitochondria. One branch utilizes discontinuous density gradient centrifugation to isolate semipure mitochondria suitable for functional assays but unsuitable for protein localization because of endoplasmic reticulum (ER) contamination. The other branch utilizes self-forming density gradient ultracentrifugation to remove ER and yield ultrapure mitochondria that are suitable for investigating protein localization but functionally compromised. Through this process, we evaluated brain mitochondria protein content and observed the absence of Cav1.2α1 and other previously reported mitochondrial proteins, including the NMDA receptor, ryanodine receptor 1, monocarboxylate transporter 1, excitatory amino acid transporter 1, and glyceraldehyde 3-phosphate dehydrogenase. Conversely, we confirmed mitochondrial localization of several plasma membrane proteins previously reported to also localize to mitochondria. We expect this dual-process isolation procedure will enhance understanding of brain mitochondria in both health and disease. |
| Databáze: | OpenAIRE |
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