Conformation-Specific Genetically Encodable Intrabodies for Spatially Modulating Protein Kinase Signaling
SUMMARY
Genetically encoded synthetic antibody fragments, expressed intracellularly, to specifically bind the mTOR FKBP12-Rapamycin binding domain inhibiting mTORC1 and mTORC2 activity. Fused with localization signals, these tools enable precise, compartment-specific modulation of mTOR signaling for research and therapeutic exploration
- mTOR signaling is a fundamental cellular pathway regulating diverse processes like cell growth, metabolism, and survival. Its dysregulation is implicated in numerous diseases, including cancer, diabetes, and neurodegenerative disorders. A comprehensive understanding of mTOR's precise spatiotemporal regulation is critical for dissecting its complex roles in health and disease. There is a significant need for advanced tools to investigate location-specific mTOR signaling events, particularly in non-canonical cellular compartments, which have historically been challenging to study.
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Existing methods for modulating mTOR activity, such as small molecule inhibitors, genetic ablation, or chemical-genetic approaches, suffer from significant limitations. Small molecule inhibitors like rapamycin act systemically, lacking the subcellular spatial resolution required to dissect compartment-specific mTOR functions. Genetic ablation provides global inhibition, often leading to pleiotropic effects or lethality, making it difficult to isolate specific cellular roles. These conventional tools cannot independently manipulate mTOR activity in distinct subcellular locations, hindering detailed investigation into how location-specific signaling contributes to biological outcomes and disease progression.
- The faculty inventor developed genetically encoded synthetic antibody fragments, known as intrabodies, designed to inhibit mTOR signaling. These fragments specifically bind to the FKBP12-Rapamycin binding domain (FRB) of mTOR, interfering with substrate recruitment essential for mTORC1 and mTORC2 activity. Isolated via phage display and characterized structurally, these intrabodies engage mTOR through hydrophobic interactions, mimicking natural substrates. When expressed in human cells, they competitively block mTOR's interactions with key binding partners, effectively inhibiting phosphorylation of downstream targets like S6K1 and Akt. Their genetic encodability allows fusion with localization signals to direct inhibition to specific subcellular compartments.
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This technology stands out due to its unprecedented subcellular spatial resolution, enabling targeted mTOR inhibition within specific cellular compartments like the nucleus, cytosol, or plasma membrane—a capability not achievable with conventional small molecule inhibitors or genetic knockout methods. Being genetically encodable, these inhibitors offer precise control over expression in specific cell types or under particular promoters. Furthermore, their conformational specificity allows for discrimination between distinct mTORFRB states, providing unique insights into allosteric regulation. This offers a powerful new tool for dissecting location-specific mTOR signaling events and their roles in cellular processes, which were previously challenging to investigate.
ADVANTAGES
ADVANTAGES
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Enables precise, subcellular spatial control of mTOR inhibition
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Genetically encodable for targeted expression in specific cell types or under specific promoters
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Provides a powerful tool for dissecting location-specific mTOR signaling events
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Offers insights into mTOR conformational states and allosteric regulation
APPLICATIONS
- Research tool
- Drug target validation platform
- Precision gene therapy development
PUBLICATIONS