The DBTL cycles we carried out so far allowed us to establish a completely genetically encodable protein – TRI-LYTAC. Using a TfR (HAI) binding peptide, we obtained a molecule with small dimensions, suitable for transport across the blood-brain barrier (BBB), with good cargo transfer capabilities and better kinetics compared to other LYTAC versions.
In short, the TRI-LYTAC is a modular lysosome-targeting chimaera designed to include three elements:
(1) a tau binding single-chain variable fragment (antibodies);
(2) a TfR (HAI) binding peptide for BBB transport and increased rate of internalisation; and
(3) a dimeric IGF-2R binder to route internalised cargo to the lysosomes.
The individual parts for building a TRI-LYTAC protein, included in the iGEM registry, are listed in the Parts page.
The modular nature of TRI-LYTAC makes it widely usable for other neurodegenerative diseases, oncology and environmental remediation applications.
In the case of many neurodegenerative diseases, toxic extracellular proteins aggregate and act as “seeds” for propagation. TRI-LYTAC can be re-programmed for multiple conditions because it enables brain delivery, selective binding of pathological extracellular proteins and transport to lysosomes for degradation (clean-up). TRI-LYTAC would direct extracellular “toxic seeds” to lysosomes, breaking propagation cycles in all cases. However, only the binding domain would need to change (e.g. to match misfolded α-synuclein oligomers in case of Parkinson’s disease (Peelaerts & Baekelandt 2016.) or polyglutamine (polyQ) fragments in case of Huntington’s disease) (Trajkovic et al., 2017). The trafficking modules (IGF2R + TfR) would remain the same.
Our research into oncological applications, extremely limited, revealed nevertheless that TRI-LYTAC might contribute to the “clean-up” of extracellular and surface immunosuppressive factors in tumors—while sparing healthy tissue. This could be achieved by combining a tumor-targeting module (instead of our current TfR binding peptide) , a disease-specific binder (siilar to our AT8 tau scFv) and a lysosome-shuttling ligand (simialr to our IGF-2 binder).
The oncology application would need to swap the disease-specific binding module. Instead of the AT8 scFv, it is possible to insert, for example, an anti-PD-L1 scFv or an anti-EGFR nanobody to capture immunosuppressive checkpoints or oncogenic receptors in tumors. Meanwhile, the HAI peptide continues to act as a tumor-penetrating shuttle (many cancers overexpress TfR) and the dimeric IGF-2 drives lysosomal degradation of the captured targets.
The novelty of such an approach would be the combination of tumor homing, selective targeting, and enforced degradation into a single chimaera, which is different from classical antibodies or checkpoint inhibitors, which block rather than physically remove targets. This design would tackle both membrane-bound and soluble factors with the same scaffold.
The current TRI-LYTAC construct can be adapted for environmental remediation by swapping the disease-specific binder for a module that recognizes pollutants or toxins. For instance, instead of the AT8 scFv, one could insert an scFv, nanobody, or peptide aptamer against microplastic particles, pesticide residues, or heavy metal–binding proteins, while the HAI peptide is replaced with an environmental targeting motif (e.g., a cellulose-binding domain for soil, or a hydrophobin tag for water–oil interfaces) to concentrate the chimaera in contaminated sites. The dimeric IGF-2 (or an analogous receptor ligand) would then act as the universal degradation/clearance module, routing the captured pollutant–chimaera complexes into engineered microbial lysosomes or vacuoles for safe breakdown.
This design directly parallels the Alzheimer’s construct—disease binder → targeting shuttle → lysosomal routing—but innovates by repurposing a therapeutic degradative scaffold into a bio-remediation tool.
The novelty lies in combining programmable pollutant recognition, environment-specific targeting, and forced cellular degradation, a strategy distinct from conventional bioremediation, which relies on slow, natural metabolic pathways rather than modular synthetic clearance systems.