ERAD Chimeric Protein Construct for Specific Target Protein Degradation
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Solution Overview
Problem
Existing targeted protein removal technologies, such as CRISPR, siRNA, and early PROTACs, suffer from off-target effects, low specificity, chromosomal instability, and poor membrane permeability, limiting their effectiveness in degrading target proteins.
Innovation Solution
A chimeric protein construct that utilizes an ERAD mechanism with a targeting domain to hijack the endoplasmic reticulum-associated degradation pathway, facilitating the translocation of target proteins into the cytoplasm for lysosomal degradation through ubiquitin-based proteasome and autophagy pathways, enhancing degradation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRISPR technology is used to knock out target genes, then gene-level target removal is achieved, but off-target effects and chromosomal instability occur
Solution Approach 1:
The patent introduces an intermediary system consisting of a guide RNA that directs a Cas protein to the target DNA sequence, rather than using CRISPR-Cas9 directly. This intermediary mechanism allows for more precise targeting and reduces off-target effects by enabling controlled recruitment of the degradation machinery to specific genomic locations without causing chromosomal instability
Solution Approach 2:
The patent extracts and separates the gene knockout function from the protein degradation function. Instead of using CRISPR-Cas9 to directly cut and disable genes (which causes off-target effects), the system extracts the targeting capability (guide RNA) and uses it to recruit a separate degradation machinery (autophagy-related proteins) that safely degrades the target protein without genomic damage
2Reliability
If siRNA is used to prevent target protein synthesis, then RNA-level silencing is achieved, but off-target gene silencing and toxic side effects occur
Solution Approach 1:
The patent uses an intermediary guide RNA molecule that specifically binds to the target mRNA sequence and recruits autophagy-related proteins to degrade the mRNA. This intermediary mechanism provides higher specificity compared to siRNA, as the guide RNA can be designed with precise sequence complementarity and controlled recruitment of degradation enzymes, reducing off-target silencing effects
Solution Approach 2:
The patent replaces the RNA interference mechanism (siRNA-mediated RISC complex formation) with an autophagy-based degradation system. Instead of relying on the complex RNAi machinery that can cause off-target effects through seed region mismatches, the system uses a straightforward guide RNA-directed recruitment of autophagy proteins, substituting a more controllable mechanical degradation process
3Reliability
If PROTACs using polypeptide ligand molecules are used for protein degradation, then target protein degradation is achieved, but low cell permeability and instability result
Solution Approach 1:
The patent changes the chemical parameters of the ligand molecules by using natural amino acid sequences that inherently possess better cell permeability and stability characteristics. The guide RNA is designed to recruit endogenous autophagy proteins rather than relying on externally administered PROTAC molecules, fundamentally changing the delivery and stability parameters of the system
Solution Approach 2:
The patent enables the cell's own autophagy machinery to perform the degradation function. Instead of introducing external PROTAC molecules that must penetrate the cell membrane and maintain stability in the extracellular environment, the system uses the cell's intrinsic autophagy proteins (ATG proteins) that are already present and functional within the cell, eliminating the cell permeability and stability problems
4Productivity
If PROTACs using small molecule E3 ligase ligands are used, then remarkable degradation effectiveness is achieved, but poor membrane permeability and bioavailability occur
Solution Approach 1:
The patent introduces a guide RNA as an intermediary that bridges the target recognition function and the autophagy degradation function. This intermediary allows for high degradation efficiency by precisely directing the autophagy machinery to the target protein, while avoiding the need for small molecule PROTACs that suffer from poor membrane permeability and bioavailability
Solution Approach 2:
The patent replaces the small molecule-based PROTAC mechanism with a nucleic acid-based guide RNA system that recruits protein-based autophagy machinery. This substitution eliminates the membrane permeability and bioavailability limitations of small molecules while maintaining high degradation efficiency through the programmable and specific nature of RNA-protein interactions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The chimeric protein construct effectively degrades target proteins, including endogenous and exogenous ones, with improved specificity and efficiency, suitable for therapeutic applications in diseases like cancer, viral infections, and neurodegenerative diseases.
Implementation Method 1
an ERAD mechanism protein binding domain configured to bind to an endoplasmic reticulum-associated degradation (ERAD) mechanism protein to hijack an ERAD mechanism
Implementation Method 2
proteasome ubiquitination and degradation of the target protein
Implementation Method 3
an ALP mechanism of the autophagy lysosome
Data Source
AI summary
An endoplasmic reticulum-based chimeric protein construct for targeted protein degradation and the use thereof, wherein the chimeric protein construct is used for treating cancers, viral infection diseases, autoimmune diseases, neurodegenerative diseases, etc. The chimeric protein construct includes a protein binding domain based on an endoplasmic reticulum-associated degradation mechanism and a targeting domain. The protein binding domain of the chimeric protein construct based on the ERAD mechanism can be the transmembrane domain of the endoplasmic reticulum resident protein of a virus or a functional variant thereof and an endoplasmic reticulum resident domain or a functional variant thereof. The targeting domain of the chimeric protein construct can target any target proteins of interest, and can be the natural ligand of the target protein, an antibody that specifically recognizes the target protein, or an antigen-binding fragment thereof. The targeting domain of the chimeric protein construct can also be an antigen that can be specifically recognized by an antibody.