Nelli Mnatsakanyan, PhD
Research & Publications
Biography
News
Research Summary
We have recently found that the mitochondrial ATP synthase forms a large voltage-gated channel with the biophysical characteristics of mitochondrial permeability transition pore (mPTP). We have shown that minimal unit required for the channel activity is the ATP synthase monomer with its membrane embedded c-subunit ring.
1. We have optimized the large-scale purification procedure of ATP synthase from porcine heart mitochondria for cryo-EM structural studies and single-channel recordings. We confirmed the monomeric state of ATP synthase by cryo-electron microscopy of ATP synthase reconstituted proteoliposomes. We then used this same monomeric ATP synthase reconstituted proteoliposome for patch-clamp recordings, which revealed that the ATP synthase monomers form large conductance, Ca2+-sensitive and voltage-gated channels with the biophysical characteristics of mPTP.
2. We have purified human ATP synthase c-subunit from HEK 293 cells. We have also heterologously overexpressed and purified human c-subunit from E. coli plasma membranes. Human c-subunit purified from both HEK 293 cells and E.coli forms a large conductance channels, which can be gated by purified F1 portion of ATP synthase.
3. We observed that disassembly/dissociation of ATP synthase F1 from FO occurs when we expose primary hippocampal neurons to glutamate toxicity (elevated intracellular calcium conditions), suggesting that the non-reversible dissociation of F1 from FO occurs in pathology and confirming that the F1 ATPase is forming the gate of the c-subunit channel.
4. We have used CRISPR-Cas9 technology to knocked out five/six alleles of the ATP5G1/G2/G3 genes encoding ATP synthase c-subunit in mouse embryonic stem cells, which resulted in 85% KD of c-subunit in mitochondrial membranes. Patch-clamp recordings of c-subunit KD mitoplasts demonstrate low conductance activity that is not sensitive to calcium and CsA and lack the high-conductance (~1.5 nS) mPTP-like activity.
5. We have successfully made and purified the low-conductance mutant of c-subunit from HEK 293 cells. We are now generating CRISPR/Cas9-edited mice, which will have the low probability of c-subunit channel (mPTP) opening. We will introduce these mutations in transgenic Alzheimer's disease (AD) mice to study if they will protect the mice from the onset of AD-like features. We hypothesize that this mouse will be protected from degenerative diseases of brain and heart.
These findings confirm that the ATP synthase monomer and more specifically its membrane-embedded c-subunit ring forms the high conductance channel of mitochondrial permeability transition.
Coauthors
Research Interests
Alzheimer Disease; Mitochondria; Synaptic Transmission; Apoptosis; Neurodegenerative Diseases; ATP Synthetase Complexes; alpha7 Nicotinic Acetylcholine Receptor
Research Images
Selected Publications
- ATP synthase c-subunit ring as the channel of mitochondrial permeability transition: Regulator of metabolism in development and degeneration.Mnatsakanyan N, Jonas EA. ATP synthase c-subunit ring as the channel of mitochondrial permeability transition: Regulator of metabolism in development and degeneration. Journal Of Molecular And Cellular Cardiology 2020, 144:109-118.
- The new role of F1Fo ATP synthase in mitochondria-mediated neurodegeneration and neuroprotection.Mnatsakanyan N, Jonas EA. The new role of F1Fo ATP synthase in mitochondria-mediated neurodegeneration and neuroprotection. Experimental Neurology 2020, 332:113400.
- ATP Synthase c-Subunit Leak Causes Aberrant Cellular Metabolism in Fragile X Syndrome.Licznerski P, Park HA, Rolyan H, Chen R, Mnatsakanyan N, Miranda P, Graham M, Wu J, Cruz-Reyes N, Mehta N, Sohail S, Salcedo J, Song E, Effman C, Effman S, Brandao L, Xu GN, Braker A, Gribkoff VK, Levy RJ, Jonas EA. ATP Synthase c-Subunit Leak Causes Aberrant Cellular Metabolism in Fragile X Syndrome. Cell 2020, 182:1170-1185.e9.
- A mitochondrial megachannel resides in monomeric F1FO ATP synthase.Mnatsakanyan N, Llaguno MC, Yang Y, Yan Y, Weber J, Sigworth FJ, Jonas EA. A mitochondrial megachannel resides in monomeric F1FO ATP synthase. Nature Communications 2019, 10:5823.
- ATP Synthase C-Subunit-Deficient Mitochondria Have a Small Cyclosporine A-Sensitive Channel, but Lack the Permeability Transition Pore.Neginskaya MA, Solesio ME, Berezhnaya EV, Amodeo GF, Mnatsakanyan N, Jonas EA, Pavlov EV. ATP Synthase C-Subunit-Deficient Mitochondria Have a Small Cyclosporine A-Sensitive Channel, but Lack the Permeability Transition Pore. Cell Reports 2019, 26:11-17.e2.
- Parkinson's disease protein DJ-1 regulates ATP synthase protein components to increase neuronal process outgrowth.Chen R, Park HA, Mnatsakanyan N, Niu Y, Licznerski P, Wu J, Miranda P, Graham M, Tang J, Boon AJW, Cossu G, Mandemakers W, Bonifati V, Smith PJS, Alavian KN, Jonas EA. Parkinson's disease protein DJ-1 regulates ATP synthase protein components to increase neuronal process outgrowth. Cell Death & Disease 2019, 10:469.
- Vitamin E Prevents ΔN-Bcl-xL-associate Mitochondrial Dysfunction in Primary Hippocampal Neurons (P14-024-19).Park HA, Mnatsakanyan N, Broman K, Jonas E. Vitamin E Prevents ΔN-Bcl-xL-associate Mitochondrial Dysfunction in Primary Hippocampal Neurons (P14-024-19). Current Developments In Nutrition 2019, 3.
- Identification of two segments of the γ subunit of ATP synthase responsible for the different affinities of the catalytic nucleotide-binding sites.Mnatsakanyan N, Li Y, Weber J. Identification of two segments of the γ subunit of ATP synthase responsible for the different affinities of the catalytic nucleotide-binding sites. The Journal Of Biological Chemistry 2019, 294:1152-1160.
- Alpha-Tocotrienol Prevents Oxidative Stress-Mediated Post-Translational Cleavage of Bcl-xL in Primary Hippocampal Neurons.Park HA, Mnatsakanyan N, Broman K, Davis AU, May J, Licznerski P, Crowe-White KM, Lackey KH, Jonas EA. Alpha-Tocotrienol Prevents Oxidative Stress-Mediated Post-Translational Cleavage of Bcl-xL in Primary Hippocampal Neurons. International Journal Of Molecular Sciences 2019, 21.
- Examination of Mitochondrial Ion Conductance by Patch Clamp in Intact Neurons and Mitochondrial Membrane PreparationsJonas EA, Mnatsakanyan N. Chapter: Techniques to Investigate Mitochondrial Function in Neurons. 2017, DOI: 10.1007/978-1-4939-6890-9_11
- Inhibition of Bcl-xL prevents pro-death actions of ΔN-Bcl-xL at the mitochondrial inner membrane during glutamate excitotoxicity.Park HA, Licznerski P, Mnatsakanyan N, Niu Y, Sacchetti S, Wu J, Polster BM, Alavian KN, Jonas EA. Inhibition of Bcl-xL prevents pro-death actions of ΔN-Bcl-xL at the mitochondrial inner membrane during glutamate excitotoxicity. Cell Death And Differentiation 2017, 24:1963-1974.
- Physiological roles of the mitochondrial permeability transition pore.Mnatsakanyan N, Beutner G, Porter GA, Alavian KN, Jonas EA. Physiological roles of the mitochondrial permeability transition pore. Journal Of Bioenergetics And Biomembranes 2017, 49:13-25.
- Direct interaction of the resistance to inhibitors of cholinesterase type 3 protein with the serotonin receptor type 3A intracellular domain.Nishtala SN, Mnatsakanyan N, Pandhare A, Leung C, Jansen M. Direct interaction of the resistance to inhibitors of cholinesterase type 3 protein with the serotonin receptor type 3A intracellular domain. Journal Of Neurochemistry 2016, 137:528-38.
- Cell death disguised: The mitochondrial permeability transition pore as the c-subunit of the F(1)F(O) ATP synthase.Jonas EA, Porter GA, Beutner G, Mnatsakanyan N, Alavian KN. Cell death disguised: The mitochondrial permeability transition pore as the c-subunit of the F(1)F(O) ATP synthase. Pharmacological Research : The Official Journal Of The Italian Pharmacological Society 2015, 99:382-92.
- Functional Chimeras of GLIC Obtained by Adding the Intracellular Domain of Anion- and Cation-Conducting Cys-Loop Receptors.Mnatsakanyan N, Nishtala SN, Pandhare A, Fiori MC, Goyal R, Pauwels JE, Navetta AF, Ahrorov A, Jansen M. Functional Chimeras of GLIC Obtained by Adding the Intracellular Domain of Anion- and Cation-Conducting Cys-Loop Receptors. Biochemistry 2015, 54:2670-2682.
- Experimental determination of the vertical alignment between the second and third transmembrane segments of muscle nicotinic acetylcholine receptors.Mnatsakanyan N, Jansen M. Experimental determination of the vertical alignment between the second and third transmembrane segments of muscle nicotinic acetylcholine receptors. Journal Of Neurochemistry 2013, 125:843-54.
- The beta subunit loop that couples catalysis and rotation in ATP synthase has a critical length.Mnatsakanyan N, Kemboi SK, Salas J, Weber J. The beta subunit loop that couples catalysis and rotation in ATP synthase has a critical length. The Journal Of Biological Chemistry 2011, 286:29788-96.
- The role of the betaDELSEED-loop of ATP synthase.Mnatsakanyan N, Krishnakumar AM, Suzuki T, Weber J. The role of the betaDELSEED-loop of ATP synthase. The Journal Of Biological Chemistry 2009, 284:11336-45.
- ATP synthase with its gamma subunit reduced to the N-terminal helix can still catalyze ATP synthesis.Mnatsakanyan N, Hook JA, Quisenberry L, Weber J. ATP synthase with its gamma subunit reduced to the N-terminal helix can still catalyze ATP synthesis. The Journal Of Biological Chemistry 2009, 284:26519-25.
- F0 cysteine, bCys21, in the Escherichia coli ATP synthase is involved in regulation of potassium uptake and molecular hydrogen production in anaerobic conditions.Mnatsakanyan N, Bagramyan K, Vassilian A, Nakamoto RK, Trchounian A. F0 cysteine, bCys21, in the Escherichia coli ATP synthase is involved in regulation of potassium uptake and molecular hydrogen production in anaerobic conditions. Bioscience Reports 2002, 22:421-30.
- The nucleotide binding affinities of two critical conformations of Escherichia coli ATP synthase.Li Y, Valdez NA, Mnatsakanyan N, Weber J. The nucleotide binding affinities of two critical conformations of Escherichia coli ATP synthase. Archives Of Biochemistry And Biophysics 2021, 707:108899.