膜物理状态对溶酶体钾离子通透性的影响。

Influence of membrane physical state on lysosomal potassium ion permeability.

作者信息

Wang Jun, Zhang Guo-Jiang

机构信息

Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China.

出版信息

Cell Biol Int. 2005 Jun;29(6):393-401. doi: 10.1016/j.cellbi.2004.12.002.

DOI:10.1016/j.cellbi.2004.12.002

PMID:15996490

Abstract

Lysosomal permeability to potassium ions is an important property of the organelle. Influence of the membrane physical state on the potassium ion permeability of isolated lysosomes was assessed by measuring the membrane potential with bis(3-propyl-5-oxoisoxazol-4-yl)pentamethine oxonol and monitoring the lysosomal proton leakage with p-nitrophenol. The membrane fluidity of lysosomes was modulated by treatment with membrane fluidizer benzyl alcohol and rigidifier cholesteryl hemisuccinate. Changes in the membrane order were examined by steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene. The measurements of membrane potential and proton leakage demonstrated that the permeability of lysosomes to potassium ions increased with rigidification of their membranes by cholesteryl hemisuccinate treatment at 37 degrees C, and decreased with fluidization of their membranes by benzyl alcohol treatment at 2 degrees C. The changes in ion permeability could be recovered by fluidizing the rigidified membranes and rigidifying the fluidized membranes. The results suggest that the physical states of lysosomal membranes play an important role in the regulation of their K(+) permeability.

摘要

溶酶体对钾离子的通透性是该细胞器的一个重要特性。通过使用双（3-丙基-5-氧代异恶唑-4-基）五甲川草酚测量膜电位，并使用对硝基苯酚监测溶酶体质子泄漏，评估了膜物理状态对分离的溶酶体钾离子通透性的影响。通过用膜流化剂苯甲醇和硬化剂胆固醇半琥珀酸酯处理来调节溶酶体的膜流动性。通过1,6-二苯基-1,3,5-己三烯的稳态荧光各向异性来检查膜有序性的变化。膜电位和质子泄漏的测量表明，在37℃下用胆固醇半琥珀酸酯处理使溶酶体膜硬化时，溶酶体对钾离子的通透性增加，而在2℃下用苯甲醇处理使溶酶体膜流化时，其通透性降低。离子通透性的变化可以通过使硬化的膜流化和使流化的膜硬化来恢复。结果表明，溶酶体膜的物理状态在其K(+)通透性的调节中起重要作用。