Labeling lysosomes and tracking lysosome-dependent apoptosis with a cell-permeable activity-based probe.
In this study, we describe a new strategy for labeling and tracking lysosomes with a cell-permeable fluorescent activity-based probe (CpFABP) that is covalently bound to select lysosomal proteins. Colocalization studies that utilized LysoTracker probes as standard lysosomal markers demonstrated that our novel probe is effective in specifically labeling lysosomes in various kinds of live cells. Furthermore, our studies revealed that this probe has the ability to label fixed cells, permeabilized cells, and NH4Cl-treated cells, unlike LysoTracker probes, which show ineffective labeling under the same conditions. Remarkably, when applied to monitor the process of lysosome-dependent apoptosis, our probe not only displayed the expected release of lysosomal cathepsins from lysosomes into the cytosol but also revealed additional information about the location of the cathepsins during apoptosis, which is undetectable by other chemical lysosome markers. These results suggest a wide array of promising applications for our probe and provide useful guidelines for its use as a lysosome marker in lysosome-related studies.
Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, and ‡Key Laboratory of Biomedical Photonics of Ministry of Education, Department of Biomedical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, P. R. China.
Fengkai
F
Fan
Si
S
Nie
Dongmei
D
Yang
Meijie
M
Luo
Hua
H
Shi
Yu-Hui
YH
Zhang
D000818:Animals; D017209:Apoptosis; D019556:COS Cells; D002403:Cathepsins / Q000032:analysis / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D010539:Permeability; D013194:Staining and Labeling
D005456:Fluorescent Dyes; D002403:Cathepsins