George Khelashvili, Ph.D.

Assistant Professor of Physiology and Biophysics

  • Assistant Professor of Computational Biophysics in the Institute for Computational Biomedicine

212-746-6348

1300 York Avenue, Room LC-501A
New York, NY 10065


Techniques

Research Areas


Research Summary:

Image created by H. Adam Steinberg, https://www.artforscience.com

The overall goal of the research projects in the lab is to uncover dynamic mechanisms in fundamental biological processes of signal transduction by cell surface proteins in the categories of receptors (such as G protein-coupled receptors, GPCRs), transporters in the family of Neurotransmitter:Sodium-Symporters (NSS), and lipid scramblases. Special emphasis is on understanding how the spatial organization and function of these molecular machines are regulated by the cell membrane, its components (i.e. cholesterol, various lipids), and interactions with the rich environment of the cell’s proteins. We approach these research topics with advanced quantitative methods of theoretical and computational biophysics, developed and utilized at the highest level of each specialty. We pursue interdisciplinary and multi-scale strategies that integrate biophysical theory and computation with biophysical measurements and molecular cell biology experimentation. Our approach takes advantage of an abundance of molecular level insights from experimental explorations of the function and interactions of membrane-associated signaling proteins, and interprets them in a novel quantitative multi-scale framework to yield insights based on energetics, and experimentally testable hypotheses we validate with respect to mechanisms by which membrane properties and remodeling (e.g. curvature, lipid segregation) affect protein function, organization and signaling-associated interactions that are of major importance to cell physiology.

Recent Publications:

  1. Khelashvili, G, Kots, E, Cheng, X, Levine, MV, Weinstein, H. The allosteric mechanism leading to an open-groove lipid conductive state of the TMEM16F scramblase. Commun Biol. 2022;5 (1):990. doi: 10.1038/s42003-022-03930-8. PubMed PMID:36123525 PubMed Central PMC9484709.
  2. Cheng, X, Khelashvili, G, Weinstein, H. The permeation of potassium ions through the lipid scrambling path of the membrane protein nhTMEM16. Front Mol Biosci. 2022;9 :903972. doi: 10.3389/fmolb.2022.903972. PubMed PMID:35942471 PubMed Central PMC9356224.
  3. Morra, G, Razavi, AM, Menon, AK, Khelashvili, G. Cholesterol occupies the lipid translocation pathway to block phospholipid scrambling by a G protein-coupled receptor. Structure. 2022;30 (8):1208-1217.e2. doi: 10.1016/j.str.2022.05.010. PubMed PMID:35660161 PubMed Central PMC9356978.
  4. Zhang, X, Xie, H, Iaea, D, Khelashvili, G, Weinstein, H, Maxfield, FR et al.. Phosphatidylinositol phosphates modulate interactions between the StarD4 sterol trafficking protein and lipid membranes. J Biol Chem. 2022;298 (7):102058. doi: 10.1016/j.jbc.2022.102058. PubMed PMID:35605664 PubMed Central PMC9207681.
  5. Kots, E, Mlynarczyk, C, Melnick, A, Khelashvili, G. Conformational transitions in BTG1 antiproliferative protein and their modulation by disease mutants. Biophys J. 2022; :. doi: 10.1016/j.bpj.2022.04.023. PubMed PMID:35459639 .
  6. Xie, H, Rojas, A, Maisuradze, GG, Khelashvili, G. Mechanistic Kinetic Model Reveals How Amyloidogenic Hydrophobic Patches Facilitate the Amyloid-β Fibril Elongation. ACS Chem Neurosci. 2022;13 (7):987-1001. doi: 10.1021/acschemneuro.1c00801. PubMed PMID:35258946 PubMed Central PMC8986627.
  7. Khelashvili, G, Menon, AK. Phospholipid Scrambling by G Protein-Coupled Receptors. Annu Rev Biophys. 2022;51 :39-61. doi: 10.1146/annurev-biophys-090821-083030. PubMed PMID:34932914 PubMed Central PMC9521775.
  8. Heath, GR, Kots, E, Robertson, JL, Lansky, S, Khelashvili, G, Weinstein, H et al.. Localization atomic force microscopy. Nature. 2021;594 (7863):385-390. doi: 10.1038/s41586-021-03551-x. PubMed PMID:34135520 PubMed Central PMC8697813.
  9. Cater, RJ, Chua, GL, Erramilli, SK, Keener, JE, Choy, BC, Tokarz, P et al.. Structural basis of omega-3 fatty acid transport across the blood-brain barrier. Nature. 2021;595 (7866):315-319. doi: 10.1038/s41586-021-03650-9. PubMed PMID:34135507 PubMed Central PMC8266758.
  10. Khelashvili, G, Pillai, AN, Lee, J, Pandey, K, Payne, AM, Siegel, Z et al.. Unusual mode of dimerization of retinitis pigmentosa-associated F220C rhodopsin. Sci Rep. 2021;11 (1):10536. doi: 10.1038/s41598-021-90039-3. PubMed PMID:34006992 PubMed Central PMC8131606.
  11. Ashkar, R, Doktorova, M, Heberle, FA, Scott, HL, Barrera, FN, Katsaras, J et al.. Reply to Nagle et al.: The universal stiffening effects of cholesterol on lipid membranes. Proc Natl Acad Sci U S A. 2021;118 (20):. doi: 10.1073/pnas.2102845118. PubMed PMID:33952694 PubMed Central PMC8157964.
  12. Khelashvili, G, Plante, A, Doktorova, M, Weinstein, H. Ca2+-dependent mechanism of membrane insertion and destabilization by the SARS-CoV-2 fusion peptide. Biophys J. 2021;120 (6):1105-1119. doi: 10.1016/j.bpj.2021.02.023. PubMed PMID:33631204 PubMed Central PMC7899928.
  13. Khelashvili, G, Plante, A, Doktorova, M, Weinstein, H. Ca 2+ -dependent mechanism of membrane insertion and destabilization by the SARS-CoV-2 fusion peptide. bioRxiv. 2021; :. doi: 10.1101/2020.12.03.410472. PubMed PMID:33299996 PubMed Central PMC7724664.
  14. Chakraborty, S, Doktorova, M, Molugu, TR, Heberle, FA, Scott, HL, Dzikovski, B et al.. How cholesterol stiffens unsaturated lipid membranes. Proc Natl Acad Sci U S A. 2020;117 (36):21896-21905. doi: 10.1073/pnas.2004807117. PubMed PMID:32843347 PubMed Central PMC7486787.
  15. Rodríguez-Espigares, I, Torrens-Fontanals, M, Tiemann, JKS, Aranda-García, D, Ramírez-Anguita, JM, Stepniewski, TM et al.. Publisher Correction: GPCRmd uncovers the dynamics of the 3D-GPCRome. Nat Methods. 2020;17 (8):861-862. doi: 10.1038/s41592-020-0928-3. PubMed PMID:32704182 .
  16. Schachter, I, Allolio, C, Khelashvili, G, Harries, D. Confinement in Nanodiscs Anisotropically Modifies Lipid Bilayer Elastic Properties. J Phys Chem B. 2020;124 (33):7166-7175. doi: 10.1021/acs.jpcb.0c03374. PubMed PMID:32697588 PubMed Central PMC7526989.
  17. Rodríguez-Espigares, I, Torrens-Fontanals, M, Tiemann, JKS, Aranda-García, D, Ramírez-Anguita, JM, Stepniewski, TM et al.. GPCRmd uncovers the dynamics of the 3D-GPCRome. Nat Methods. 2020;17 (8):777-787. doi: 10.1038/s41592-020-0884-y. PubMed PMID:32661425 .
  18. Gotfryd, K, Boesen, T, Mortensen, JS, Khelashvili, G, Quick, M, Terry, DS et al.. X-ray structure of LeuT in an inward-facing occluded conformation reveals mechanism of substrate release. Nat Commun. 2020;11 (1):1005. doi: 10.1038/s41467-020-14735-w. PubMed PMID:32081981 PubMed Central PMC7035281.
  19. Khelashvili, G, Chauhan, N, Pandey, K, Eliezer, D, Menon, AK. Exchange of water for sterol underlies sterol egress from a StARkin domain. Elife. 2019;8 :. doi: 10.7554/eLife.53444. PubMed PMID:31799930 PubMed Central PMC6940019.
  20. Khelashvili, G, Cheng, X, Falzone, ME, Doktorova, M, Accardi, A, Weinstein, H et al.. Membrane lipids are both the substrates and a mechanistically responsive environment of TMEM16 scramblase proteins. J Comput Chem. 2020;41 (6):538-551. doi: 10.1002/jcc.26105. PubMed PMID:31750558 PubMed Central PMC7261202.
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