MEMBRANOUS INTERMEDIATES IN ENDOCYTOSIS ARE LABILE, AS SHOWN IN A TEMPERATURE-SENSITIVE MUTANT
MEMBRANOUS INTERMEDIATES IN ENDOCYTOSIS ARE LABILE, AS SHOWN IN A TEMPERATURE-SENSITIVE MUTANT
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DOI：
10.1073/pnas.86.13.4968
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发表时间：
1989-07-01
影响因子：
11.1
通讯作者：
ROTH, TF
中科院分区：
文献类型：
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作者：
KESSELL, I;HOLST, BD;ROTH, TF
膜小管是一种多形性内吞腔室，在受体介导的内吞作用中起作用，在哺乳动物吸收上皮和昆虫卵母细胞中尤为普遍。为了确定这些小管是否会消失，并研究它们与其他内吞噬中间体的时间关系，我们研究了温度敏感突变体果蝇（Drosophila melanogaster, shibiretsl）卵母细胞卵黄形成过程中的这些小管。将shibire卵母细胞的温度从19℃升高到29℃1分钟，会导致这些膜小管的丢失。膜在小管中的比例从19℃时的36%下降到29℃5 min后的1.5%。同时，表面膜的数量从19℃时的64%增加到29℃时5分钟后的98%，导致表面膜内陷向皮层深处延伸。在29℃时，质膜细胞质表面布满被包覆的凹坑，细胞外表面包裹有电子致密物质。从29℃恢复到19℃或26℃1-2分钟后，皮层中含有细胞外辣根过氧化物酶的小管迅速重新出现。这些数据表明，管状中间体是易逝的结构，温度冲击(i)迅速阻止它们从质膜形成，（ii）导致现有的小管迅速再循环到质膜，（iii）迅速逆转，因为新形成的小管从细胞表面获得膜和内容物。
Membranous tubules, especially prevalent in mammalian absorptive epithelia and insect oocytes, are one of the pleomorphic endocytic compartments that have a role in receptor-mediated endocytosis. To determine whether these tubules are evanescent, and to investigate their temporal relationships with other endocytic intermediates, we studied these tubules during oocyte vitellogenesis in the temperature-sensitive mutant Drosophila melanogaster, shibiretsl. Raising the temperature of shibire oocytes for 1 min from 19.degree.C to 29.degree.C caused a loss of these membranous tubules. The percentage of membrane in tubules decreased from 36% at 19.degree.C to 1.5% after 5 min at 29.degree.C. Concomitantly, the amount of surface membrane increased from 64% at 19.degree.C to 98% after 5 min at 29.degree.C, causing surface membrane invaginations to extend deeper into the cortex. At 29.degree.C the cytoplasmic face of the plasma membrane was studded with coated pits, and the extracellular face was coated with electron-dense material. Return from 29.degree.C to either 19.degree.C or 26.degree.C for 1-2 min produced a rapid reappearance of tubules containing extracellular horseradish peroxidase in the cortex. These data suggest that tubular intermediates are evanescent structures, and that temperature shock (i) rapidly blocks their formation from the plasma membrane, (ii) causes existing tubules to rapidly recycle to the plasma membrane, and (iii) is rapidly reversed, as newly formed tubules derive their membrane and content from the cell surface.