Education

Postdoctoral Fellow
Max Planck Institute for Molecular Cell Biology & Genetics, 2012
Ph.D.
University of Pennsylvania, 2008

Areas of Interests

Research Interests

Membrane structure & post-translational lipidation

Research Information

Membrane structure & post-translational lipidation

Research interests:
– The structure of eukaryotic membranes
– Post-translational mechanisms for targeting membrane microdomains
– Functional diversity in protein transmembrane domains

Though the structure-function relationship of polypeptides is one of the core dogmas of molecular cell biology, the functional aspects of lipid structure have been little explored. The existence of lipid rafts, i.e. lateral membrane domains arising from preferential interactions between specific lipids, suggests that such structure could be an important contributor to cell function and pathophysiology. The involvement of these domains in diverse cellular functions (e.g. growth factor signaling and membrane trafficking) and disease processes – including cancer, autoimmunity, and Alzheimer’s disease – has confirmed this potential and energized the field. Recent compelling evidence has definitively resolved the controversy about the existence of membrane domains; however, the mechanisms by which they regulate cell function remain speculative due to a lack of quantitative, robust tools for their investigation.

Our primary research goals are: (1) to investigate the physical principles behind the formation of membrane domains; (2) to uncover the mechanisms by which these domains regulate cell signaling; and (3) to develop strategies to modulate these mechanisms for treatment of human disease.

Functional segregation: lateral structure of mammalian membranes
To study lipid rafts in biological membranes, we use an exciting and novel tool in membrane biology, phase separation in Giant Plasma Membrane Vesicles (GPMVs). These plasma membranes, isolated directly from live cells, allow direct, rapid, and quantitative analysis of component partitioning to raft phases in eukaryotic cell membranes. Additionally, independent quantification of protein enzymatic/binding activity permits analysis of the raft-dependence of these characteristics.

Ongoing project #1: using GPMVs to assay raft-dependent ligand binding and oligomerization of the Epidermal Growth Factor Receptor (EGFR) and its oncogenic homolog HER2.

Ongoing project #2:measuring changes in raft formation, physical properties, and composition of plasma membranes of mesenchymal stem cells as they proceed through terminal differentiation.

Greasing the way: post-translation micro domain targeting mechanisms
Protein selectivity underlies the functionality of plasma membrane nanodomains. The mechanisms by which proteins are selectively recruited to ordered lipid domains remain ambiguous. Our previous work shows that most transmembrane proteins require modification by lipids, specifically saturated fatty acids, to incorporate into lipid raft domains. One such lipidation is palmitoylation, a modification that can be observed on hundreds of proteins involved in a myriad of cellular functions. We are using a combination of biochemical tools and bio-orthogonal click chemistry, to investigate the dynamics of these important modifications and their impact on cell function.

Ongoing project #3: developing a quantitative palmitoylation assay and using it to characterize palmitoylation dynamics in immune and cancer cell signaling.

A PEEK INSIDE THE CORE: THE SECRET LIVES OF PROTEIN TRANSMEMBRANE DOMAINS
Though most research into membrane protein focuses on lumenal ligands or intracellular effectors, there is significant structural and functional information encoded into membrane spanning domains, usually alpha-helices. I use synthetic biology and protein engineering to elucidate the molecular code behind the micro domain partitioning and function of transmembrane proteins.

Ongoing project #4: designing transmembrane domain mutants of EGFR to determine the requirements for its raft association and oligomer formation.

Ongoing project #5: developing drugs to specifically target protein transmembrane domains.

The overall goal of my research is to develop strategies to modulate the mechanisms by which lateral membrane structure regulates cell function for potential treatment of human diseases.

Levental Lab

Publications

Publication Information

References

  • Burns M, Wisser K, Wu J, Levental I, Veatch SL. (2017). Miscibility Transition Temperature Scales with Growth Temperature in a Zebrafish Cell Line. Biophys J. May 25. pii: S0006-3495(17)30505-2. doi: 10.1016/j.bpj.2017.04.052.
  • Cornell CE, McCarthy NLC, Levental KR, Levental I, Brooks NJ, Keller SL.  (2017).  n-Alcohol Length Governs Shift in Lo-Ld Mixing Temperatures in Synthetic and Cell-Derived Membranes. Biophys J; pii: S0006-3495(17)30757-9.
  • Ganesan L, Shieh P, Bertozzi CR, Levental I. (2017).  Click-Chemistry Based High Throughput Screening Platform for Modulators of Ras Palmitoylation.  Sci Rep.; 7:41147.
  • He J, Zhang F, Tay LW, Boroda S, Nian W, Levental KR, Levental I, Harris TE, Chang JT, Du G. (2017). Lipin-1 regulation of phospholipid synthesis maintains endoplasmic reticulum homeostasis and is critical for triple-negative breast cancer cell survival. FASEB J. Jul;31(7):2893-2904. doi: 10.1096/fj.201601353R. Epub 2017 Mar 27.
  • Levental KR, Surma MA, Skinkle AD, Lorent JH, Zhou Y, Klose C, Chang JT, Hancock JF, Levental I.  (2017). Polyunsaturated fatty acids direct differentiation of the membrane phenotype in mesenchymal stem cells to potentiate osteogenesis. Science Advances; in press.
  • Lorent JH, Diaz-Rohrer BB, Lin X, Spring K, Gorfe AA, Levental KR, Levental I. (2017). Structural determinants and functional consequences of protein affinity for membrane rafts. Nature Communications; in press.
  • Rissanen S, Grzybek M, Orłowski A, Róg T, Cramariuc O, Levental I, Eggeling C, Sezgin E, Vattulainen I. (2017). Phase Partitioning of GM1 and Its Bodipy-Labeled Analog Determine Their Different Binding to Cholera Toxin. Front Physiol. May 9;8:252. doi: 10.3389/fphys.2017.00252. eCollection 2017.
  • Sezgin E, Levental I, Mayor S, Eggeling C. (2017). The mystery of membrane organization: composition, regulation and roles of lipid rafts. Nat Rev Mol Cell Biol. Jun;18(6):361-374. doi: 10.1038/nrm.2017.16. Epub 2017 Mar 30.
  • Levental KR, Lorent JH, Lin X, Skinkle AD, Surma MA, Stockenbojer EA, Gorfe AA, Levental I. (2016). Polyunsaturated lipids regulate membrane domain stability by tuning membrane order. Biophys J; 110(8):1800-10.
  • Lin X, Lorent JH, Skinkle AD, Levental KR, Waxham MN, Gorfe AA*, Levental I*. (2016). Domain stability in biomimetic membranes driven by lipid polyunsaturation. J Phys Chem; 120(46):11930-11941.
  • Lin X, Zhang S, Ding H, Levental I*, Gorfe AA*. (2016). The aliphatic chain of cholesterol modulates bilayer interleaflet coupling and domain registration. FEBS Lett; 590(19):3368-3374.
  • Tisza MJ, Zhao W, Fuentes JS, Prijic S, Chen X, Levental I*, Chang JT*. (2016). Motility and stem cell properties induced by EMT require destabilization of lipid rafts. Oncotarget; doi: 10.18632/oncotarget.9928.
  • Tulodziecka K, Diaz-Rohrer BB, Farley MM, Chan RB, Di Paolo G, Levental KR, Waxham MN*, Levental I*. (2016). Remodeling of the postsynaptic plasma membrane during neural development. Mol Biol Cell; 7;27(22):3480-3489.
  • Beck-García K, Beck-García E, Bohler S, Zorzin C, Sezgin E, Levental I, Alarcón B, Schamel WW. (2015). Nanoclusters of the resting T cell antigen receptor (TCR) localize to non-raft domains.  Biochim Biophys Acta; 1853(4): 802-9.
  • Ihida-Stansbury K, Ames J, Chokshi M, Aiad N, Sanyal S, Kawabata KC, Levental I, Sundararaghavan HG, Burdick JA, Janmey P, Miyazono K, Wells RG, Jones PL. (2015). Role played by Prx1-dependent extracellular matrix properties in vascular smooth muscle development in embryonic lungs. Pulm Circ; 5(2): 382-7.
  • Sezgin E, Gutmann T, Buhl T, Dirkx R, Grzybek M, Coskun Ü, Solimena M, Simons K, Levental I*, Schwille P*. (2015). Adaptive lipid packing and bioactivity in membrane domains.PLOS One; 10(4):e0123930.
  • Wolfe AR, Debeb BG, Lacerda L, Larson R, Bambhroliya A, Huang X, Bertucci F, Finetti P, Birnbaum D, Van Laere S, Diagaradjan P, Ruffell B, Trenton NJ, Chu K, Hittelman W, Diehl M, Levental I, Ueno NT, Woodward WA. (2015). Simvastatin prevents triple-negative breast cancer metastasis in pre-clinical models through regulation of FOXO3a. Breast Cancer Res Treat;154(3):495-508.
  • Diaz-Aguilar B, Levental K, Simons K,Levental I. (2014). Membrane raft association is a determinant of plasma membrane localization. Proc Natl Acad Sci USA (PNAS). 111(23):8500-5. Selected for cover article ; 48 citations
  • Schwarzer R, Levental I, Gramatica A, Scolari S, Buschmann V, Veit M, Herrmann A. (2014). The cholesterol-binding motif of the HIV-1 glycoprotein gp41 regulates lateral sorting and oligomerization. Cell Microbiol. 16(10):1565-81.
  • Zhou Y, Maxwell KN, Sezgin E, Lu M, Liang H, Hancock JF, Dial EJ, Lichtenberger LM, Levental I. (2013). Bile acids modulate signaling by functional perturbation of plasma membrane domains. J. Biol. Chem., 288(50):35660-70.
  • Sezgin E, Chwastek G, Aydogan G, Levental I, Simons K, Schwille P. (2013). Photoconversion of bodipy-labeled lipid analogues.  Chembiochem., 14, 695-698.
  • Sezgin E, Kaiser HJ, Baumgart T, Schwille P, Simons K, Levental I. (2012). Elucidating membrane structure and protein behavior using Giant Plasma Membrane Vesicles. Nat Protoc., 3;7(6):1042-51. COVER ARTICLE.
  • Levental I, Grzybek M, Simons K. (2012). Raft domains of various properties and compositions in plasma membrane vesicles.  PNAS, USA.
  • Sezgin E, Levental I, Schwarzmann G, Mueller V, Belov VN, Eggeling C, Coskun U, Simons K, Schwille P. (2012). Partitioning, diffusion, and ligand binding of raft lipid analogs in model and cellular plasma membranes. Biochem Biophys Acta.  1818(7):1777-84.
  • Levental I, Lingwood D, Grzybek M, Coskun U, Simons K. (2010).  Palmitoylation regulates raft affinity for the majority of integral raft proteins.  PNAS.
  • Levental I, Grzybek M, Simons K. (2010). Greasing their way: lipid modifications determine protein association with membrane rafts. Biochemistry.
  • Levental I*, Levental KR*, Klein EA, Assoian RK, Miller RT, Wells RG, Janmey PA. (2010). A simple indentation device for measuring micrometer-scale tissue stiffness.  Journal of Physics: Condensed Matter. *authors contributed equally
  • Levental I, Byfield FJ, Chowdhury P, Gai F, Baumgart T, Janmey PA.  (2009). Cholesterol-dependent phase separation in cell-derived giant plasma-membrane vesicles. Biochemical Journal.
  • Levental I*, Christian DA*, Wang YH, Madara JJ, Discher DE, Janmey PA. (2009). Calcium-Dependent Lateral Organization in Phosphatidylinositol 4,5-Bisphosphate (PIP2)- and Cholesterol-Containing Monolayers. Biochemistry. *authors contributed equally
  • Solon J*, Levental I*, Sengupta K, Georges PC, Janmey PA. (2007). Fibroblast adaptation and stiffness matching to soft elastic substrates. Biophysical Journal *authors contributed equally
  • Levental I, Georges PC, Janmey PA. (2007). Soft biological materials and their impact on cell function. Soft Matter.