Julia Sajman

Prof. Eilon Sherman lab, Rocah Institute of Physics, HUJI

In our lab we apply methods of single molecule localization microscopy (SMLM). We aim to research immune system cells, especially T lymphocytes and their interaction with target cells. T cells have a significant role in the mechanism of the acquired immune system: CD4+ T cells act as helpers, activating other cells in the immune reaction; CD8+ T cells are cytotoxic, which kill infected cells. We are intriguing to investigate specific proteins involved in the cell-to-cell recognition complex and following T cell activation pathway.

Our methods allow us to visualize immunological synapse in super-resolution level, as single proteins. We use photo-activatble protein tags for PALM (photo-activated localization microscopy) for imaging processes in live cells and their dynamics. We also use synthetic fluorophores for STORM (direct stochastic optical reconstruction) in multiple colors for immune-fluorescence of live and fixated cells.

Special photo-activatble fluorophores in combination with statistical and image processing methods allows us to study signaling complexes in single molecule detail in intact (fixed and live) cells with resolution down to ~20nm. We can estimate the clustering of different proteins; it’s dynamics on T cell membrane prior and after cell activation; recruitment and timing of intracellular cascade. 

Current research

Using SMLM and PALM methods we investigate activation of artificial CAR receptors expressed on CD8+ lymphocytes. This project is with collaboration with Ihilov hospital, Tel-Aviv. Researchers in Ihilov and Tel-Aviv University developed CARs that targets special sugars common on some cancer cells and leading to selective T cell activation against this cancer. Expression of those CAR receptors on patient lymphocyte leads to patient specific therapy. We are involved in this project, studying the activation pathway of T cells by CAR after the meeting with cancer cells. Also we look for better structure of this CAR and how improve their action against cancer cells.

1. I Friedrich, M Eizenbach, J Sajman, H Ben-Bassat, A Levitzki, A cellular screening assay to test the ability of PKR to induce cell death in mammalian cells, 2005 Molecular Therapy 12 (5), 969-975. Citation 12. SJR Ranking Q1 citations 12
2. KJ Simpson-Lavy, J Sajman, D Zenvirth, M Brandeis, APC/C^Cdh1 specific degradation of Hsl1 and Clb2 is required for proper stress responses of S. cerevisiae, 2009, Cell cycle 8 (18), 3006-3012.. SJR Ranking Q1 citations 22
3. KJ Simpson-Lavy, YS Oren, O Feine, J Sajman, T Listovsky, M Brandeis, Fifteen years of APC/cyclosome: a short and impressive biography, 2010, Biochemical Society Transactions 38 (1), 78-82. SJR Ranking Q1, citations 28.
4. Y Neve-Oz, Y Razvag, J Sajman, E Sherman, Mechanisms of localized activation of the T cell antigen receptor inside clusters, 2015, Biochimica et Biophysica Acta (BBA)-Molecular Cell Research 1853 (4), 810-821. SJR Ranking Q1, citations 29.
5. J Sajman, D Zenvirth, M Nitzan, H Margalit, KJ Simpson-Lavy, Y Reiss, et al, Degradation of Ndd1 by APC/C^Cdh1 generates a feed forward loop that times mitotic protein accumulation, (2015), Nature communications 6, 7075. SJR Ranking Q1, citations 14.
6. J Sajman, M Trus, D Atlas, E Sherman, The L-type voltage-gated calcium channel co-localizes with syntaxin 1A in nano-clusters at the plasma membrane, (2017), Scientific reports 7 (1), 11350. SJR Ranking Q1, citations 9.
7. Y Neve-Oz, J Sajman, Y Razvag, E Sherman, InterCells: a generic Monte-Carlo simulation of intercellular interfaces captures nanoscale patterning at the immune synapse, 2018, Frontiers in immunology 9, 2051. SJR Ranking Q1, citations 4.

Y Razvag, Y Neve-Oz, J Sajman, M Reches, E Sherman, Nanoscale kinetic segregation of TCR and CD45 in engaged microvilli facilitates early

1. T cell activation, (2018), Nature communications 9 (1), 732.,  SJR Ranking Q1, citations 48.
2. O Yakovian, R Schwarzer, J Sajman, Y Neve-Oz, Y Razvag, A Herrmann,et al, Gp41 dynamically interacts with the TCR in the immune synapse and promotes early T cell activation, (2018), Scientific reports 8 (1), 9747.,  SJR Ranking Q1, citations 8.

3. Y Neve-Oz, J Sajman, Y Razvag, E Sherman, InterCells: a generic Monte-Carlo simulation of intercellular interfaces captures nanoscale patterning at the immune synapse (2018) , Frontiers in immunology 9, 2051. SJR Ranking Q1 citations 4

1. S Schidorsky, X Yi, Y Razvag, J Sajman, K Hermon, S Weiss, E Sherman, Synergizing superresolution optical fluctuation imaging with single molecule localization microscopy, (2018), Methods and applications in fluorescence 6 (4), 045008 SJR Ranking Q1, citations 5.
2. Y Razvag, Y Neve-Oz, J Sajman, O Yakovian, M Reches, E Sherman, T Cell Activation through Isolated Tight Contacts, 2019, Cell Reports 29 (11), 3506-3521. SJR Ranking Q1. citations 13

6. Yakovian, J Sajman, R Arafeh, Y Neve-Oz, M Alon, Y Samuels, et al., MEK inhibition reverses aberrant signaling in melanoma cells through reorganization of NRas and BRAF in self nano-clusters (2020), Cancer Research SJR Ranking Q1
7. E Servili, M Trus, J Sajman, E Sherman, D Atlas, Elevated basal transcription can underlie timothy channel association with autism related disorders (2020), Progress in Neurobiology, 101820. SJR Ranking Q1 citations 2
8. J Sajman, Y Razvag, S Schidorsky, S Kinrot, K Hermon, O Yakovian & E Sherman (2021), Adhering interacting cells to two opposing coverslips allows super-resolution imaging of cell-cell interfaces, Communications Biology volume 4, Article number: 439. SJR Ranking Q1

   Conferences:

1. Friedrich, I., Shir, A., Itin, J., Ben-Bassat, H., and Levitzki, A. Selective killing of cancer cells by specific activation of the double-stranded RNA dependent protein kinase – PKR, 11^th International Conference of the international society for cancer gene therapy (ISCGT), London, England, 2002. Poster presentation.
2. Sajman J., Zenvirth D., Nitzan M ., Reiss Y., Simpson-Lavy K.J. and Brandeis M., The APC/C – Ndd1 Feed forward Loop, 2008. Talk.
3. Sajman J, New APC/Cyclosome substrates in yeast, Yeast conference in Weizmann institute, 2013. Poster presentation.
4. Sajman J., Trus M., Atlas D., Sherman E., L-type Channel and Syntaxin 1A co-localize in nano-clusters at the plasma membrane. Nano-Science and Nano-technology conference, Dead sea, Israel, 2017 and in Frontiers in single molecules biophysics conference, Nave Ilan, Israel, 2017. Poster presentation.
5. Sajman J, Razvag Y., Schidorsky S., Kinrot S., Hermon K., Yakovian O. & Sherman E., Adhering interacting cells to two opposing coverslips allows super-resolution imaging of cell-cell interfaces at The 2nd Immuno-oncological Meeting of the Israel Immunological Society (IIS), on February 22-24, 2022, in Haifa, Israel. A "honorably-mentioned poster" presentation.