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Published on: August 15, 2017
A Sensitive Green-Red FRET Sensor for Calpain-1 Utilizing Heterodimeric Fluorescent Proteins from Distinct
Fangfang Yang1, Mengying Deng1, Xiaorong Pan2
1Research Center for Primate Neuromodulation and Neuroimaging, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
Abstract:
Calpain-1, a calcium-dependent cysteine protease, plays a pivotal role in various biological functions. However, real-time monitoring of its activity has been limited by the lack of high-performance calpain sensors. Here, we report the development of iFoCAL, a sensitive and specific fluorescence resonance energy transfer (FRET) sensor for calpain-1, which employs mClover3 and mScarletX, a newly engineered green-red FRET pair with weak interactions. Using iFoCAL, we revealed distinct spatiotemporal patterns of calpain-1 activation: gradual and global activation in whole cells during endoplasmic reticulum (ER) calcium release, fast and focal activation in axons during mechanical stress, and region-specific activation in a Parkinson's disease model. These findings provide the first direct evidence of distinct calpain-1 dynamics across diverse cellular contexts.
