Biotechnology Medical Research Tools

Keywords Infrared, Protease, Sensor, Apoptosis, Imaging

Invention novelty

This invention includes the design and use of protease imaging reporters which can be detected in deep tissue. These can be used to monitor the effects of protease inhibitors, proteases and protease mediated processes including apoptosis related to the treatment of disease states such as cancer.

Value proposition

Proteases play key roles in many diseases, such as cancer, HIV, HCV, Parkinson’s disease, and Huntington’s disease. The ability to better monitor protease activity in vivo would lead to improved treatments and treatment outcomes. Current commercially available protease assays rely on systems whereby protease cleavage causes a loss of quenching signal and result in high background. However, iProtease, a genetically encoded system which uses infrared fluorescent proteins, results in a gain of signal upon proteolysis. Additional advantages of this invention are:

No exogenous molecules such as chemical dyes Protease specificity Safe for biological assays Improved contrast over fluorescent dye-based labeling systems Visualize protease activity in the deep tissue of live animals Facilitate drug discovery screenings of protease inhibitors in animal models Tissue-specific and whole-animal imaging optimization

Technology description

Scientists at UCSF have developed an infrared fluorescent imaging reporter, iProtease, for the detection of protease activity in cells and animals. The reporter becomes fluorescent only when activated by a protease, creating better contrast than GFP-based fluorescence resonance energy transfer-based systems, as well as fluorescent dye-based labeling systems. The iProtease system is versatile and can be easily used to design specific protease reporters by genetically designing their cleavage sequence into the iProtease construct. It has been successfully used in designing the executioner caspases (caspase 3 and 7), TEV protease and hepatitis C virus (HCV) NS3/4A protease. These fluorogenic protease reporters have successfully and specifically detected caspase 3/7, TEV protease, and NS3/4A protease activity in live cell systems as well as in small animals.


Protease inhibitor drug screening Research tool for monitoring protease activity in live cell and animal systems Cell lines and transgenic animals can be created expressing the imaging reporter

Looking for partners

To develop and commercialize this technology as a research tool for proteases and protease inhibitors for therapeutic or industrial applications

Stage of development


Related materials

To, T.-L., Piggott, B. J., Makhijani, K., Yu, D., Jan, Y.-N., & Shu, X. (2015). Rationally designed fluorogenic protease reporter visualizes spatiotemporal dynamics of apoptosis in vivo. PNAS, 112(11), 3338–3343.

Data availability


Patent status


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