TEMPERATURE-DEPENDENCE OF PROTEIN-DEGRADATION, AUTOPHAGIC SEQUESTRATION AND MITOCHONDRIAL SUGAR UPTAKE IN RAT HEPATOCYTES
TEMPERATURE-DEPENDENCE OF PROTEIN-DEGRADATION, AUTOPHAGIC SEQUESTRATION AND MITOCHONDRIAL SUGAR UPTAKE IN RAT HEPATOCYTES
复制标题
大鼠肝细胞中蛋白质降解、自噬封存和线粒体糖摄取的温度依赖性
DOI：
10.1016/0167-4889(87)90167-4
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发表时间：
1987-07-06
期刊：
影响因子：
--
通讯作者：
SEGLEN, PO
中科院分区：
文献类型：
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作者：
GORDON, PB;KOVACS, AL;SEGLEN, PO
在离体大鼠肝细胞中，溶酶体（丙胺敏感）蛋白降解和非溶酶体蛋白降解的能量依赖（凝乳抑素敏感）部分受到温度的强烈影响，这两个过程的活化能（Ea）约为25 kcal/mol。相比之下，非溶酶体降解的能量独立（凝乳抑制素抗性）部分的Ea约为。只有10千卡/摩尔。电注入的[14C]蔗糖在可沉积细胞器中的固存表现出明显的温度依赖性。通过提取洋地黄苷，有可能区分适度温度敏感线粒体糖摄取(Ea约。12千卡/摩尔)和强烈依赖温度的自噬隔离(Ea约为。22千卡每摩尔)。在20℃以下无明显的自噬隔离。C.与内吞作用的早期步骤相比，固存过程对温度更敏感，并且可能代表整个自噬-溶酶体途径的主要控制步骤。
Lysosomal (propylamine-sensitive) protein degradation as well as the energy-dependent (chymostatin-sensitive) part of the non-lysosomal protein degradation was found to be strongly affected by temperature in isolated rat hepatocytes, the activation energy (Ea) being about 25 kcal/mol for both processes. In contrast, the energy-independent (chymostatin-resistant) part of the non-lysosomal degradation had an Ea of approx. 10 kcal/mol only. Sequestration of electroinjected [14C]sucrose into sedimentable organelles showed a pronounced temperature dependence. By means of digitonin extraction it was possible to distinguish between a moderately temperature-sensitive mitochondrial sugar uptake (Ea approx. 12 kcal/mol) and a strongly temperature-dependent autophagic sequestration (Ea approx. 22 kcal/mol). There was no significant autophagic sequestration below 20.degree. C. The sequestration process is more temperature-sensitive than, for example, the early steps of endocytosis, and is likely to represent the major controlling step in the overall autophagic-lysosomal pathway.