Serine phosphorylation regulates paxillin turnover during cell migration.
Serine phosphorylation regulates paxillin turnover during cell migration.
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DOI：
10.1186/1478-811x-4-8
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发表时间：
2006-11-22
期刊：
影响因子：
--
通讯作者：
Boyer B
中科院分区：
文献类型：
--
作者：
Abou Zeid N;Vallés AM;Boyer B
桩蛋白作为一种衔接蛋白定位于粘着斑。这种蛋白质在细胞迁移过程中通过酪氨酸、丝氨酸和苏氨酸残基上的磷酸化来调节。这些磷酸化中的大多数与细胞迁移的不同步骤的调节有关。桩蛋白的两个主要的磷酸化位点是丝氨酸188和190，它们与细胞外基质的粘附有关。然而，这种磷酸化事件的功能仍然未知。本工作的目的是确定桩蛋白磷酸化残基S188和S190在细胞迁移的调节中的作用。我们使用了NBT-II上皮细胞，当将其铺在胶原蛋白上时，可以诱导其迁移。为了研究桩蛋白丝氨酸188/190在细胞迁移中的作用，我们构建了EGFP标记的桩蛋白突变体，其中S188/S190突变为不可磷酸化的丙氨酸残基。我们提供的证据表明，桩蛋白的多聚泛素化后的蛋白酶体降解的调节。在胶原蛋白上的活性细胞迁移期间，桩蛋白被保护免于蛋白酶体依赖性降解。我们证明丝氨酸188/190的磷酸化对于胶原蛋白的保护作用是必要的。在努力了解桩蛋白保护降解的生理相关性，我们表明，表达桩蛋白S188/190 A干扰突变体的细胞扩散较少，具有降低的扩散活性，但迁移更活跃。我们的数据首次表明，丝氨酸调节的桩蛋白降解在膜动力学的调节中起着关键作用，因此，在细胞运动的控制。
Paxillin acts as an adaptor protein that localizes to focal adhesion. This protein is regulated during cell migration by phosphorylation on tyrosine, serine and threonine residues. Most of these phosphorylations have been implicated in the regulation of different steps of cell migration. The two major phosphorylation sites of paxillin in response to adhesion to an extracellular matrix are serines 188 and 190. However, the function of this phosphorylation event remains unknown. The purpose of this work was to determine the role of paxillin phosphorylation on residues S188 and S190 in the regulation of cell migration. We used NBT-II epithelial cells that can be induced to migrate when plated on collagen. To examine the role of paxillin serines 188/190 in cell migration, we constructed an EGFP-tagged paxillin mutant in which S188/S190 were mutated into unphosphorylatable alanine residues. We provide evidence that paxillin is regulated by proteasomal degradation following polyubiquitylation of the protein. During active cell migration on collagen, paxillin is protected from proteasome-dependent degradation. We demonstrate that phosphorylation of serines 188/190 is necessary for the protective effect of collagen. In an effort to understand the physiological relevance of paxillin protection from degradation, we show that cells expressing the paxillin S188/190A interfering mutant spread less, have reduced protrusive activity but migrate more actively. Our data demonstrate for the first time that serine-regulated degradation of paxillin plays a key role in the modulation of membrane dynamics and consequently, in the control of cell motility.