CIQUIBIC, UNC-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA, Córdoba, Republica Argentina,
Histochem Cell Biol. 2013 Nov;140(5):507-20. doi: 10.1007/s00418-013-1095-8. Epub 2013 Apr 27.
The increased studies on urinary bladder umbrella cells as an important factor for maintaining the permeability barrier have suggested new pathways for the discoidal/fusiform endocytic vesicles which is one of the main features of the umbrella cells. The biological role of these vesicles was defined, for many years, as a membrane reservoir for the umbrella cell apical plasma membrane which are subject to an increased tension during the filling phase of the micturition cycle and, therefore, the vesicles are fused with the apical membrane. Upon voiding, the added membrane is reinserted via a non-clathrin or caveolin-dependant endocytosis thereby restoring the vesicle cytoplasmic pool. However, in the last decade, new evidence appeared indicating alternative pathways of the endocytic vesicles different than the cycling process of exocytosis/endocytosis. The purpose of this review is to analyze the molecular modulators, such as membrane lipids and proteins, in the permeability of endocytic vesicles, the sorting of endocytosed material to lysosomal degradation pathway and recycling of both membrane and fluid phases.
越来越多的研究表明，尿路上皮伞细胞作为维持通透性屏障的重要因素，为盘状/梭形内吞小泡提供了新的途径，这是伞细胞的主要特征之一。这些小泡的生物学作用多年来一直被定义为伞细胞顶质膜的膜储备库，在排尿周期的充盈相中，顶质膜会受到更大的张力，因此小泡与顶质膜融合。在排空时，通过非网格蛋白或 caveolin 依赖性内吞作用重新插入添加的膜，从而恢复小泡细胞质池。然而，在过去十年中，出现了新的证据表明，内吞小泡的途径不同于胞吐/胞吞的循环过程。本文的目的是分析分子调节剂，如膜脂质和蛋白质，在小泡通透性、内吞物质分选到溶酶体降解途径以及膜和流体相的再循环中的作用。
