Durrbach A, Raposo G, Tenza D, Louvard D, Coudrier E
CNRS-ERS 1984, 19 rue Guy Moquet 94801 Villejuif, France.
Traffic. 2000 May;1(5):411-24. doi: 10.1034/j.1600-0854.2000.010506.x.
We investigate, in this study, the potential involvement of an acto-myosin-driven mechanism in endocytosis of polarized cells. We observed that depolymerization of actin filaments using latrunculin A decreases the rate of transferrin recycling to the basolateral plasma membrane of Caco-2 cells, and increases its delivery to the apical plasma membrane. To analyze whether a myosin was involved in endocytosis, we produced, in this polarized cell line, truncated, non-functional, brush border, myosin I proteins (BBMI) that we have previously demonstrated to have a dominant negative effect on endocytosis of unpolarized cells. These non-functional proteins affect the rate of transferrin recycling and the rate of transepithelial transport of dipeptidyl-peptidase IV from the basolateral plasma membrane to the apical plasma membrane. They modify the distribution of internalized endocytic tracers in apical multivesicular endosomes that are accessible to fluid phase tracers internalized from apical and basolateral plasma membrane domains. Altogether, these observations suggest that an acto-myosin-driven mechanism is involved in the trafficking of basolaterally internalized molecules to the apical plasma membrane.
在本研究中，我们探究了肌动蛋白-肌球蛋白驱动机制在极化细胞内吞作用中的潜在作用。我们观察到，用拉特肌醇A使肌动蛋白丝解聚会降低转铁蛋白循环至Caco-2细胞基底外侧质膜的速率，并增加其向顶端质膜的转运。为分析肌球蛋白是否参与内吞作用，我们在这种极化细胞系中产生了截短的、无功能的刷状缘肌球蛋白I蛋白（BBMI），我们之前已证明其对非极化细胞的内吞作用具有显性负效应。这些无功能蛋白影响转铁蛋白循环速率以及二肽基肽酶IV从基底外侧质膜向顶端质膜的跨上皮运输速率。它们改变了内化的内吞示踪剂在顶端多囊泡内体中的分布，这些内体可被从顶端和基底外侧质膜结构域内化的液相示踪剂所接触。总之，这些观察结果表明，肌动蛋白-肌球蛋白驱动机制参与了从基底外侧内化的分子向顶端质膜的运输。
