Knottin Peptide Bifunctional Molecules for Lysosomal Targeting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current targeted protein degradation (TPD) platforms face limitations due to the cytosolic localization of the ubiquitin proteasome system and targetable autophagy machinery, restricting them to proteins with cytosolic domains and requiring cell-permeable degraders, which hampers the degradation of proteins with non-cytosolic localization.
Innovation Solution
Development of bifunctional molecules comprising a knottin peptide moiety that binds to cell surface molecules and a lysosomal targeting moiety, facilitating targeted degradation via the endosomal/lysosomal pathway, allowing for the degradation of cell surface proteins by shuttling them to lysosomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cytosolic degradation pathways (UPS or autophagy) are used, then cell-permeable degraders can be designed, but proteins with non-cytosolic localization cannot be degraded
Solution Approach 1:
The bifunctional molecule is divided into two distinct moieties: a cell surface molecule-binding moiety and a lysosomal targeting molecule-binding moiety. This segmentation allows each component to be optimized for its specific function, enabling targeting of non-cytosolic proteins while maintaining cell permeability through the endosomal/lysosomal pathway.
Solution Approach 2:
The endosomal/lysosomal pathway serves as an intermediary mechanism that bridges the extracellular space and intracellular degradation machinery. By utilizing this pathway, the patent enables degradation of cell surface proteins without requiring direct cytosolic access, thus expanding targetability to non-cytosolic localization.
2Adaptability or versatility
If cell surface proteins are targeted for degradation, then therapeutic relevance is improved, but access to these targets is blocked by the cell membrane
Solution Approach 1:
The endosomal/lysosomal pathway acts as an intermediary that penetrates the cell membrane barrier. The bifunctional molecule exploits this pathway to deliver cell surface proteins into the cell for degradation, effectively overcoming the membrane barrier without requiring the degrader itself to be cell-permeable in the traditional sense.
Solution Approach 2:
Instead of attempting to deliver the degrader directly into the cytosol (the conventional approach), the patent inverts the strategy by using the endosomal/lysosomal pathway to bring the target protein into the cell for degradation. This reversal of the traditional degradation paradigm enables access to cell surface targets.
3Measurement precision
If knottin peptides are used as binding moieties, then binding affinity and specificity are improved, but molecular size and synthesis complexity increase
Solution Approach 1:
The binding function is segmented into separate knottin peptide moieties that can be independently designed and optimized for specific cell surface molecules. This allows high binding affinity and specificity to be achieved through modular knottin units without requiring the entire bifunctional molecule to be excessively complex.
Solution Approach 2:
The patent utilizes the inherent structural and binding parameters of knottin peptides (such as disulfide bond arrangement and loop conformation) to achieve high binding affinity. By leveraging these pre-existing structural parameters rather than designing from scratch, the patent reduces overall molecular complexity while maintaining specificity.
Data Source
AI summary
Provided are bifunctional molecules that include a first moiety that specifically binds a cell surface molecule, and a second moiety that specifically binds a lysosomal targeting molecule. In certain embodiments, the first moiety is a knottin peptide comprising an engineered loop that binds to the cell surface molecule. The bifunctional molecules find use, e.g., for targeted degradation of cell surface molecules (e.g., proteins) via the endosomal/lysosomal pathway. Also provided are compositions and kits that include the bifunctional molecules, as well as methods of using the bifunctional molecules. Methods of making bifunctional molecules are also provided.