Journal of Biomedical Science

, Volume 14, Issue 3, pp 419–427

The fate of SPE B after internalization and its implication in SPEB-induced apoptosis

Authors

  • Chia-Wen Chang
    • Institute of Basic Medical SciencesNational Cheng Kung University Medical College
    • BiochemistryNational Cheng Kung University Medical College
  • Wan-Hua Tsai
    • Institute of Basic Medical SciencesNational Cheng Kung University Medical College
    • BiochemistryNational Cheng Kung University Medical College
  • Woei-Jer Chuang
    • Institute of Basic Medical SciencesNational Cheng Kung University Medical College
    • BiochemistryNational Cheng Kung University Medical College
  • Yee-Shin Lin
    • Institute of Basic Medical SciencesNational Cheng Kung University Medical College
    • Microbiology and ImmunologyNational Cheng Kung University Medical College
  • Jiunn-Jong Wu
    • Institute of Basic Medical SciencesNational Cheng Kung University Medical College
    • Medical Laboratory Science and BiotechnologyNational Cheng Kung University Medical College
  • Ching-Chuan Liu
    • Department of PediatricsNational Cheng Kung University Medical College
  • Pei-Jane Tsai
    • Institute of Medical Sciences, School of MedicineTzu Chi University
    • Institute of Medical Sciences, School of MedicineTzu Chi University
Article

DOI: 10.1007/s11373-007-9154-6

Cite this article as:
Chang, C., Tsai, W., Chuang, W. et al. J Biomed Sci (2007) 14: 419. doi:10.1007/s11373-007-9154-6

Summary

After streptococcal pyrogenic exotoxin B (SPE B) induces apoptosis, its fate is unknown. Using confocal time-course microscopy at 37 °C, we detected green fluorescence 20 min after adding FITC-SPE B. Orange fluorescence, an indication of co-localization of SPE B with lysosomes which were labeled with a red fluorescent probe, was maximal at 40 min and absent by 60 min. SPE B was co-precipitated with clathrin, which is consistent with endocytotic involvement. Western blotting assay also indicated that uptake of SPE B was maximal at 40 min and disappeared after 60 min. However, in the presence of chloroquine, a lysosome inhibitor, the uptake of SPE B was not detectable. The disappearance of TCA-precipitated FITC-SPE B was parallel to the appearance of TCA soluble FITC-SPE B; in the presence of chloroquine, however, no SPE B degradation occurred. Chloroquine increased the level of SPE B-induced apoptosis by inhibiting the degradation of SPE B. These results suggest that the internalization and degradation of SPE B in cells may be a host defense system that removes toxic substances by sacrificing the exposed cells.

Keywords

A549 cellapoptosisclathrininternalizationSPE B

Copyright information

© National Science Council Taipei 2007