Advantages
- A mutant SnxA protein that specifically recognizes to PI(3,5)P2 and has higher binding capacity than the natural form.
- Lower molecular weight than antibodies allows access to areas inaccessible by antibodies.
- It is expected that a highly reliable lipid biosensor will be developed using a lipid-binding probe.
Technology Overview & Background
Phosphatidylinositol phosphate (PIP) is a trace component of cell membranes and functions as an important signaling molecule within cells. In addition to reports of a decrease in PIP in the brains of Alzheimer’s disease patients, PIP is also involved in a variety of biological processes, such as membrane transport, inflammation, and cell death. Depending on the phosphorylation modification site, eight types of PI, PI3P, PI4P, PI5P, PI(3,4)P2, PI(3,5)P2, PI(4,5)P2, and PI(3,4,5)P3 exist in vivo, each having a different function and playing a characteristic role. In order to analyze these PIPs, it is necessary to use a lipid probe with strong binding power and high selectivity, but there were no suitable lipid probes for some PIPs, such as PI(3,5)P2.
In this study, the researchers focused on the endogenous (wild-type) SnxA protein of dictyostelids. The PX domain region of SnxA is known as a lipid probe that binds PI(3,5)P2. By optimizing the sequence of this region, they succeeded in developing a mutant protein that binds PI(3,5)P2 more strongly while maintaining the same high selectivity against PI(3,5)P2 as SnxA. The optimized protein is sufficiently small in molecular weight compared to antibodies that it can be used in internal sites of tissues that are difficult to access with antibodies. This is expected to further advance the analysis of PI(3,5)P2 distribution and dynamics and drug discovery research, and is expected to be used as a reliable lipid biosensor for organelle membrane analysis, exosome isolation and analysis, dead cell detection, and ELISA kits in the future.
Data
- The binding properties of the mutant SnxA protein to each PIP and other acidic phospholipids were examined, and it was confirmed that the protein maintains binding specificity to PI(3,5)P2 as well as to the PX domain of wild-type SnxA, but not to other lipids or acidic phospholipids.
- Using the method used to prepare this mutant SnxA protein, other membrane lipid-specific binding proteins such as PIP can also be efficiently isolated and prepared.
Publication
Taki NISHIMURA, et al., “Rational engineering of lipid-binding probes via high-throughput protein-lipid interaction screening.” (bioRχiv’s preprint, Jan 5, 2025)
[DOI] https://doi.org/10.1101/2025.01.05.627504
Patent
Pending (unpublished)
Principal Investigator & Academic Institution
Taki Nishimura (Professor, The University of Osaka, Institute for Protein Research)
Development Stage & Future Research Plans
- It has been identified a mutant SnxA protein that specifically binds to PI(3,5)P2 and has improved binding ability.
- It has been already established a technique for isolating soluble proteins that may bind to membrane lipids in cells.
Expectations
TECH MANAGE is now looking for pharmaceutical and diagnostic companies that are interested in using this mutant SnxA protein as a research reagent for isolation and analysis of membrane components bound by PI(3,5)P2, or that wish to use it for their in-house research and development until the product is launched on the market. In addition to this mutant SnxA protein that binds specifically to PI(3,5)P2, other PIP and lipid-specific binding proteins may also be isolated and prepared. If you are interested in this technology, we would like to propose joint development with Dr. Nishimura. In addition, we can consider the disclosure of unpublished data by concluding a NDA/CDA with The University of Osaka, as well as paid evaluation of technologies and inventions (MTA agreement, optional arrangements such as preferential negotiation rights, etc.), so please feel free to ask.
Project ID:BK-03867