Mammalian homolog of Drosophila tumor suppressor lethal (2) giant larvae interacts with basolateral exocytic machinery in Madin-Darby canine kidney cells
Mammalian homolog of Drosophila tumor suppressor lethal (2) giant larvae interacts with basolateral exocytic machinery in Madin-Darby canine kidney cells
复制标题
DOI：
10.1091/mbc.01-10-0496
复制
发表时间：
2002-01-01
影响因子：
3.3
通讯作者：
Brennwald, PJ
中科院分区：
文献类型：
--
作者：
Müsch, A;Cohen, D;Brennwald, PJ
果蝇肿瘤抑制蛋白lethal（2）giant larvae [l（2）gl]参与发育过程中上皮细胞极性的建立。最近，酵母同系物的蛋白质已被证明与后高尔基体外泌机制的组件，并调节蛋白质分泌的后期步骤。在此，我们的特点是哺乳动物同系物的l（2）gl，称为Mlgl，在上皮细胞系Madin-Darby犬肾（MDCK）。与细胞极性中的作用一致，在接触初始MDCK细胞进行细胞-细胞接触并建立极化表型后，Mlgl从细胞质定位重新分布到侧膜。需要在Mlgl的高度保守区域内的磷酸化以将蛋白质限制于侧向结构域，因为重组磷酸化突变体以非极性方式分布。来自MDCK细胞裂解物的膜结合的Mlgl与突触融合蛋白4（基底外侧膜处的胞吐机制的组分）共免疫沉淀，但不与其他质膜可溶性N-乙基马来酰亚胺敏感因子附着受体（SNARE）蛋白共免疫沉淀，所述其他质膜可溶性N-乙基马来酰亚胺敏感因子附着受体（SNARE）蛋白不存在于基底外侧膜结构域或不限于基底外侧膜结构域。这些数据表明Mlgl通过调节基底外侧胞吐作用而有助于顶-基底外侧极性。
The Drosophila tumor suppressor protein lethal (2) giant larvae [l(2)gl] is involved in the establishment of epithelial cell polarity during development. Recently, a yeast homolog of the protein has been shown to interact with components of the post-Golgi exocytic machinery and to regulate a late step in protein secretion. Herein, we characterize a mammalian homolog of l(2)gl, called Mlgl, in the epithelial cell line Madin-Darby canine kidney (MDCK). Consistent with a role in cell polarity, Mlgl redistributes from a cytoplasmic localization to the lateral membrane after contact-naive MDCK cells make cell-cell contacts and establish a polarized phenotype. Phosphorylation within a highly conserved region of Mlgl is required to restrict the protein to the lateral domain, because a recombinant phospho-mutant is distributed in a nonpolar manner. Membrane-bound Mlgl from MDCK cell lysates was coimmunoprecipitated with syntaxin 4, a component of the exocytic machinery at the basolateral membrane, but not with other plasma membrane soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins that are either absent from or not restricted to the basolateral membrane domain. These data suggest that Mlgl contributes to apico-basolateral polarity by regulating basolateral exocytosis.