F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
Summary
A method to isolate submitochondrial vesicles enriched in F1FO ATP synthase complexes from rat brain is described. These vesicles allow the study of the activity of F1FO ATPase complex and its modulation using the technique of patch clamp recording.
Abstract
Mitochondria are involved in many important cellular functions including metabolism, survival1, development and, calcium signaling2. Two of the most important mitochondrial functions are related to the efficient production of ATP, the energy currency of the cell, by oxidative phosphorylation, and the mediation of signals for programmed cell death3.
The enzyme primarily responsible for the production of ATP is the F1FO-ATP synthase, also called ATP synthase4-5. In recent years, the role of mitochondria in apoptotic and necrotic cell death has received considerable attention. In apoptotic cell death, BCL-2 family proteins such as Bax enter the mitochondrial outer membrane, oligomerize and permeabilize the outer membrane, releasing pro-apoptotic factors into the cytosol6. In classic necrotic cell death, such as that produced by ischemia or excitotoxicity in neurons, a large, poorly regulated increase in matrix calcium contributes to the opening of an inner membrane pore, the mitochondrial permeability transition pore or mPTP. This depolarizes the inner membrane and causes osmotic shifts, contributing to outer membrane rupture, release of pro-apoptotic factors, and metabolic dysfunction. Many proteins including Bcl-xL7 interact with F1FO ATP synthase, modulating its function. Bcl-xL interacts directly with the beta subunit of F1FO ATP synthase, and this interaction decreases a leak conductance within the F1FOATPasecomplex, increasing the net transport of H+ by F1FO during F1FO ATPase activity8 and thereby increasing mitochondrial efficiency. To study the activity and modulation of the ATP synthase, we isolated from rodent brain submitochondrial vesicles (SMVs) containing F1FO ATPase. The SMVs retain the structural and functional integrity of the F1FO ATPase as shown in Alavian et al. Here, we describe a method that we have used successfully for the isolation of SMVs from rat brain and we delineate the patch clamp technique to analyze channel activity (ion leak conductance) of the SMVs.
Protocol
Representative Results
Discussion
The methods described herein enable the isolation of pure mitochondria at the end of step 1 and submitochondrial vesicles (SMVs) after step 2 from whole brain without distinction of cell phenotypes.SMVspurified by this method are essentially free of contamination by other subcellular organelles as shown in Figure 1 and our previous work (Alavian KN et al.8) and retain their structural and functional integrity prior to freezing. After freezing and thawing, isolated mitochondria o…
Declarações
The authors have nothing to disclose.
Materials
| Name | Company | Catalogue number |
| Potter-Elvehjem Tissue Grinder withPTFEPestle | Krackeler Scientific, Inc. | 1-7725T-5 |
| Eppendorf Centrifuge 5424 | Eppendorf | 5424 000.410 |
| 4639 Cell Disruption Vessel | Parr Instrument Company | 4639 |
| Ficoll | Sigma-Aldrich | F5415 |
| Polycarbonate centrifuge tubes | Beckman Coulter | P20314 |
| SW-50.1 rotor | Beckman Coulter | |
| L8-70M Ultracentrifuge | Beckman Coulter | |
| Digitonin | Sigma-Aldrich | D5628 |
| Lubrol PX (C12E9) | Calbiochem | 205534 |
| Axopatch 200B | Axon Instruments | |
| Digidata 1440A | Molecular Device | |
| pClamp10.0 | Molecular Device | |
| Manipulator | Sutter Instrument | |
| Borosilicate glass capillary | World Precision Instruments | 1308325 |
| Flaming/Brown Micropipette Puller Model P-87 | Sutter Instrument |
Referências
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