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

  • Chia-Wen Chang
  • Wan-Hua Tsai
  • Woei-Jer Chuang
  • Yee-Shin Lin
  • Jiunn-Jong Wu
  • Ching-Chuan Liu
  • Pei-Jane Tsai
  • Ming-T. Lin
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

Authors and Affiliations

  • Chia-Wen Chang
    • 1
    • 2
  • Wan-Hua Tsai
    • 1
    • 2
  • Woei-Jer Chuang
    • 1
    • 2
  • Yee-Shin Lin
    • 1
    • 3
  • Jiunn-Jong Wu
    • 1
    • 4
  • Ching-Chuan Liu
    • 5
  • Pei-Jane Tsai
    • 6
  • Ming-T. Lin
    • 6
  1. 1.Institute of Basic Medical SciencesNational Cheng Kung University Medical CollegeTainanTaiwan
  2. 2.BiochemistryNational Cheng Kung University Medical CollegeTainanTaiwan
  3. 3.Microbiology and ImmunologyNational Cheng Kung University Medical CollegeTainanTaiwan
  4. 4.Medical Laboratory Science and BiotechnologyNational Cheng Kung University Medical CollegeTainanTaiwan
  5. 5.Department of PediatricsNational Cheng Kung University Medical CollegeTainanTaiwan
  6. 6.Institute of Medical Sciences, School of MedicineTzu Chi UniversityHualienTaiwan