Igor Stagljar

MY RESEARCH OVERVIEW (GO TO SCIENTIFIC OVERVIEW)

The Stagljar lab is a recognized leader in proteomics and chemical genomics, specializing in the development of high-throughput technologies to study protein–protein interactions (PPIs) of human membrane proteins involved in cancer. The lab’s foundational work includes the creation of the Membrane Yeast Two-Hybrid (MYTH) and Mammalian Membrane Two-Hybrid (MaMTH) technologies, both of which are global standards in membrane proteomics.

As a prolific innovator and disruptor in the field, the lab has also adapted MaMTH into a robust drug screening platform (MaMTH-DS) and engineered the SIMPL/SIMPL2 and CLIP-LUX technologies. These advancements support the discovery of therapeutics targeting both membrane and soluble PPI targets. Since June 2025, Professor Stagljar has also served as the inaugural Editor-in-Chief of the Elsevier journal Disease and Therapeutics.

SCIENTIFIC RESEARCH OVERVIEW

Research in our lab is focused on membrane protein-protein interactions (PPIs), with a particular interest in disease progression due to altered signalling pathways. To this end, the lab has developed two new technologies to enable research in this notoriously difficult environment.

The first was the Membrane Yeast Two-Hybrid (MYTH) system. Based on the split-ubiquitin principle, 'bait' and 'prey' proteins are fused to Cub (C-terminal ubiquitin domain) plus a transcription factor (TF) and NubG (N-terminal domain, I13G mutation), respectively. A bait and prey interaction brings the two domains of ubiquitin into close proximity, forming pseudo-ubiquitin. This is recognized by deubiquitinating enzymes, which cleave off the TF. The TF enters the nucleus and activates a reporter system, allowing detection of interacting proteins.

MYTH has been successfully used in a number of studies, including building a comprehensive map of the yeast ABC transporter interactome (Snider et al. [2013] Nature Chemical Biology 9:565).

Mammalian Membrane Two-Hybrid (MaMTH) is a powerful evolution of MYTH, developed for use in mammalian cell lines. The MaMTH approach enables quantitative measurement of dynamic protein-protein interactions (PPIs) in vivo in the natural membrane environment of human cells. The system addresses a currently challenging area of transmembrane protein analysis, which is of keen interest to the pharmaceutical market, as membrane proteins are the major class of drug targets.  We believe that our MaMTH technology will provide a means of both increasing our basic knowledge and promoting drug-discovery, thereby making significant contributions to human health care and research.

The development of MaMTH, results of MaMTH screening assys and the potential of the system as a drug screening platform were recently published in Nature Methods (Petschnigg et al. [2014] Nature Methods 11:585)

Current projects in our lab include the following:

1. AI-Driven Drug Discovery

One of the most exciting developments in the lab is the application of our recently published quantum computing/AI-driven approach to drug discovery (Ghazi Vakili et al., 2025, Nature Biotechnology). In collaboration with Alán Aspuru-Guzik’s lab (UofT) and Insilico Medicine, we have developed an automated workflow that combines generative AI and quantum computing with our proprietary MaMTH and SIMPL2 drug discovery platforms. Our goal is to accelerate the identification of novel small molecules targeting "undruggable" proteins, such as KRAS mutants and other undruggable small GTPases. Over the next five years, we aim to apply this approach to other undruggable proteins, including ubiquitin ligases, RTKs, and phosphatases.

2. SIMPL2 and CLIP-LUX for PROTACs and Molecular Glues

Building on our expertise in protein interaction technologies, we have developed SIMPL2 and CLIP-LUX, next-generation live-cell platforms that enable highly sensitive and quantitative mapping of PPIs in real time (Yao et al., 2024; Kim et al., 2026). These technologies are uniquely suited for high-throughput identification of therapeutic molecules, including PROTACs and molecular glue degraders. Our current focus is identifying compounds targeting pharmaceutically important cancer proteins, such as receptor tyrosine kinases, immune checkpoint regulators and small GTPases.

3. Comprehensive Human Cancer Membrane Proteome (HCMP)

We are currently undertaking an ambitious project to map the interactome of numerous cancer-associated membrane proteins, collectively termed the Human Cancer Membrane Proteome (HCMP). By leveraging both our MaMTH and SIMPL-NanoLuc (SIMPL2) platforms, we are systematically mapping the protein-protein interaction networks of key families, including Receptor Tyrosine Kinases (RTKs), ABC transporters, small GTPases, GPCRs, and Solute Carriers (SLCs). This high-throughput mapping enables us to uncover previously hidden functional pathways that drive oncogenic signaling and cancer progression. This comprehensive blueprint is essential for identifying novel “druggable” vulnerabilities and provides a foundation for the next generation of precision cancer therapies.

4. Identification of PPIs Involved in Cystic Fibrosis

Cystic Fibrosis (CF) is a life-limiting genetic disorder caused by mutations in the CFTR ion channel, which lead to impaired epithelial fluid transport. The Stagljar lab is conducting a large-scale exploration of the CFTR interactome by screening a library of over 400 Solute Carrier (SLC) transporters against both wild-type and ΔF508-CFTR using our Mammalian Membrane Two-Hybrid (MaMTH) system. This research has successfully identified several novel SLC interactors that appear to regulate intracellular pH and ion balance. By integrating these interaction maps with functional FLIPR assays, we have demonstrated that certain SLC transporters can significantly modulate CFTR-mediated chloride transport. Our goal is to establish a critical framework for identifying these transporters as promising "modifier" targets for next-generation CF therapeutics.

5. Translational Applications and Industry Collaborations

Our translational research is enriched by long-standing collaborations with leading pharmaceutical and biotech companies, including Genentech, Novartis, Amgen, Merck, Insilico Medicine, and Pfizer. We are currently partnering with some of these industry leaders on several high-impact projects that leverage our proprietary PPI assays for novel target identification and accelerated drug discovery.

SELECT PUBLICATIONS

• Petschnigg, J., Groisman, B., Kotlyar, M., Taipale, M., Zheng, Y., Kurat, C.F., Sayad, A., J. Rafael Sierra, Mattiazzi Usaj, M., Snider, J., Nachman, A., Krykbaeva, I., Tsao, M-S., Moffat, J., Pawson, T., Lindquist, S., Jurisica, I. and Stagljar, I. (2014) The mammalian-membrane two-hybrid assay (MaMTH) for probing membrane-protein interactions in human cells. Nature Methods 11, 585-592.
• Yao, Z., Darowski, K., St-Denis, N., Wong, V., Offensperger, F., Villedieu, A., Amin, S., Malty, R., Aoki, H., Guo, H., Xu, Y., Iorio, C., Kotlyar, M., Emili, A., Jurisica, I., Babu, M., Neel, B.G., Gingras, A-C., and Stagljar, I. (2017) A global analysis of the receptor tyrosine kinase - protein phosphatase interactome. Molecular Cell 65, 347-360. doi: 10.1016/j.molcel.2016.12.004. [Featured on the journal cover of the January 19, 2017 issue].
• Saraon, P., Snider, J., Kalaidzidis, Y., Wybenga-Groot, L. E., Weiss, K., Rai, A., Radulovich, N., Drecun, L., Vučković, N., Vučetić, A., Wong, V., Thériault, B., Nhu-An Pham, Park, J.H., Datti, A., Wang, J., Pathmanathan, S., Aboualizadeh, F., Lyakisheva, A., Yao, Z., Wang, Y., Joseph, B., Aman, A., Moran, M.F., Prakesch, M., Poda, G., Marcellus, R., Uehling, D., Samaržija, M., Jakopović, M., Tsao, M-S., Shepherd, F.A., Sacher, A., Leighl, N., Akhmanova, A., Al-awar, R., Zerial, M., and Stagljar, I. (2020) A drug discovery platform to identify compounds that inhibit EGFR triple mutants. Nature Chemical Biology 16(5): 577-586. doi: 10.1038/s41589-020-0484-2.
• Yao, Z., Aboualizadeh, F., Kroll, J., Akula, I., Snider, J., Lyakisheva, A., Tang, P., Kotlyar, M., Jurisica, I., Boxem, M., and Stagljar, I. (2020) Split Intein Mediated Protein Ligation (SIMPL), a method for detecting protein-protein interactions and their inhibition. Nature Communications 2020 May 15;11(1): 2440. doi: 10.1038/s41467-020-16299-1.
• Yao, Z., Drecun, L., Aboualizadeh, F., Kim, S.J., Li, Z., Wood, H., Valcourt, E.J., Manguiat, K., Plenderleith, S., Yip, L., Li, X., Zhong, Z., Yue, F.Y., Closas, T., Snider, J., Tomic, J., Drews, S.J., Drebot, M.A., McGeer, A., Ostrowski, M., Mubareka, S., Rini, J.M., Owen, S., and Stagljar, I. (2021) A homogeneous split-luciferase assay for rapid and sensitive detection of anti-SARS CoV-2 antibodies. Nature Communications 2021 Mar 22;12(1):1806. doi: 10.1038/s41467-021-22102-6. [Featured on CBC’s The National, CityNews TV, Global News, Toronto Star and The Globe and Mail].
• Sun Jin Kim+, Zhong Yao+, Morgan C. Marsh, Debra M. Eckert, Michael S. Kay, Anna Lyakisheva, Maria Pasic, Aiyush Bansal, Chaim Birnboim, Prabhat Jha, Julio C. Delgado, Marc G. Elgort, Robert A. Campbell, Elizabeth A. Middleton, Igor Stagljar*, Shawn C. Owen* (2022) Homogeneous Surrogate Virus Neutralization Assay to Rapidly Assess Neutralization Activity of Anti-SARS-CoV-2 Antibodies. Nature Communications 13(1):3716 (* co-corresponding authors); DOI 10.1038/s41467-022-31300-9. [Featured on CTV News, CityNews TV, CP 24 News, Global News, Toronto Star and The Globe and Mail].
• Zhong Yao, Kim, J., Geng, B., Chen, J., Lyakisheva, A., Snider, J., Rudan Dimlic, M., Raic, S., and Stagljar, I. (2025) A Split Intein and Split Luciferase-Coupled System for Detecting Protein-Protein Interactions. Molecular Systems Biology 21(2):107-125. doi: 10.1038/s44320-024-00081-2.
• Ghazi Vakili, M., Christoph Gorgulla, C., Kumar, A.N., Bezrukov, D., Varoli, D., Aliper, A., Polykovsky, D., Padmanabha Das, K.M., Snider, J., Lyakisheva, A., Hosseini Mansob, A., Yao, Z., Bitar, L., Radchenko, E., Ding, X., Liu, J., Meng, F., Ren, F., Cao, Y., Stagljar, I.*, Aspuru-Guzik, A*., and Zhavoronkov, A.* (2025) Quantum Computing-Enhanced Algorithm Unveils Novel Inhibitors for KRAS. Nature Biotechnology, Jan 22, 2025, doi: 10.1038/s41587-024-02526-3. (* co-corresponding authors). [Voted top 10 papers of 2025 by editors of Nature Biotechnology; Featured on CNN, Psychology Today, and the journal cover of the December 2025 issue].
• Mansourabadi, A.H., Randhawa, K., Snider, J., Qu, D., Cianci, F., Kotlyar, M., Rey, G., Raco, L., Burger, D., Rak, J., Soleimani, V.D., Jurisica, I., Mazzanti, M.*, Stagljar, I.*, and Jahani-Asl, A.* (2026) An OSMR-CLIC1 cross talk drives key oncogenic pathways in glioblastoma. in press in Signal Transduction and Targeted Therapy (* co-corresponding authors).
• Kim, J., Snider, J., and Stagljar, I. (2026) CLIP-LUX: A luminescent split-ubiquitin assay using ClpS-mediated N-degron recognition for detection of protein-protein interactions in mammalian cells. Disease and Therapeutics 2, 100005. https://doi.org/10.1016/j.dist.2026.100005