期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：11
页码：3338-3343
DOI：10.1073/pnas.1502857112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceBy harnessing the unique interactions between infrared fluorescent protein and its chromophore, we have designed an infrared fluorogenic protease reporter (iProtease). A fluorogenic protease reporter is ideal for imaging protease activity in vivo, whereas a FRET-based reporter is limited by poor signal and requirement of image processing. The iProtease scaffold may be used as a core module to design reporters of various proteases with specific activity. This technology will aide important applications, including monitoring protease activity in vivo, dissecting signaling pathways that regulate protease activity, and high-throughput screening of protease inhibitors for drug development and biological study. Our work shows that phytochrome-derived infrared fluorescent protein is a promising scaffold in engineering fluorogenic reporters for visualizing spatiotemporal dynamics of cell signaling in vivo. Fluorescence resonance energy transfer-based reporters have been widely used in imaging cell signaling; however, their in vivo application has been handicapped because of poor signal. Although fluorogenic reporters overcome this problem, no such reporter of proteases has been demonstrated for in vivo imaging. Now we have redesigned an infrared fluorescent protein so that its chromophore incorporation is regulated by protease activity. Upon protease activation, the infrared fluorogenic protease reporter becomes fluorescent with no requirement of exogenous cofactor. To demonstrate biological applications, we have designed an infrared fluorogenic executioner-caspase reporter, which reveals spatiotemporal coordination between cell apoptosis and embryonic morphogenesis, as well as dynamics of apoptosis during tumorigenesis in Drosophila. The designed scaffold may be used to engineer reporters of other proteases with specific cleavage sequence.
