INFLUENCE OF MEMBRANE FLUIDITY MODIFIERS ON LYSOSOMAL OSMOTIC SENSITIVITY

Authors

  • Lu Yang,

    1. Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China
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  • Guo-Jiang Zhang,

    Corresponding author
    1. Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China
      To whom correspondence should be addressed: Guo-jiang Zhang, Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China. E-mail:zhangzl@sun5.ibp.ac.cn
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  • Yi-Gang Zhong,

    1. Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China
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  • Yan-Zhen Zheng

    1. Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China
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To whom correspondence should be addressed: Guo-jiang Zhang, Department of Cellular Biophysics, Institute of Biophysics, Academia Sinica, Beijing, 100101, P. R. China. E-mail:zhangzl@sun5.ibp.ac.cn

Abstract

Since lysosomes are prone to osmotic lysis, we have examined the correlation between their physical state and sensitivity to osmotic challenge, using agents which modify membrane fluidity. The latency loss of β-hexosaminidase after an incubation in hypotonic sucrose medium was followed under different conditions of membrane fluidity, recorded by steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene. Increasing fluidity of the lysosomal membranes with benzyl alcohol (BA) and greater rigidity caused by cholesteryl hemisuccinate (CHS) increased and decreased the enzyme latency loss, respectively. The effects of BA and CHS treatments on osmotic sensitivity were reversible subsequently by reciprocal treatments of the lysosomes with CHS and BA, respectively. The results indicate that the physical state of the membrane does indeed affect lysosomal osmotic stability.

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