Regulation of vesicle transport and cell motility by Golgi-localized Dbs.
Regulation of vesicle transport and cell motility by Golgi-localized Dbs.
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DOI：
10.4161/sgtp.28570
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发表时间：
2014-01-01
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影响因子：
--
通讯作者：
Whitehead, Ian P
中科院分区：
文献类型：
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作者：
Fitzpatrick, Ethan R;Hu, Tinghui;Whitehead, Ian P
DBS/MCF 2L最近被确定为骨关节炎的风险部位。它编码的鸟嘌呤核苷酸交换因子（Dbs）已被证明可以调节正常和肿瘤细胞的运动。在目前的研究中，我们已经确定，内源性Dbs主要表达为2种亚型，一种130 kDa的形式（Dbs-130），定位于高尔基复合体，和一种80 kDa的形式（Dbs-80），定位于内质网（ER）。我们以前已经描述了一种抑制剂，结合到RhoGEF结构域的DBS和阻断其转化活性。在这里，我们表明，抑制剂定位到高尔基体，在那里它专门与DBS-130相互作用。内源性DBS-130活性的抑制与活化Cdc 42的水平降低、高尔基体增大和布雷菲德菌素A介导的高尔基体扩散的抗性相关，表明DBS在囊泡运输中的作用。用抑制剂处理的细胞表现出从ER到高尔基体的正常蛋白质转运，但从高尔基体到质膜的转运有缺陷。抑制MDA-MB-231人乳腺肿瘤细胞中的DBS-130限制了transwell和伤口愈合测定中的运动性，但似乎对微管细胞骨架的组织没有影响。运动性的降低与高尔基体向前缘重新定向的失败有关。这与高尔基体定位一致，并表明Dbs-130调节在定向迁移期间支持细胞极化所需的分泌途径的各个方面。
DBS/MCF2L has been recently identified as a risk locus for osteoarthritis. It encodes a guanine nucleotide exchange factor (Dbs) that has been shown to regulate both normal and tumor cell motility. In the current study, we have determined that endogenous Dbs is predominantly expressed as 2 isoforms, a 130kDa form (Dbs-130) that is localized to the Golgi complex, and an 80kDa form (Dbs-80) that is localized to the endoplasmic reticulum (ER). We have previously described an inhibitor that binds to the RhoGEF domain of Dbs and blocks its transforming activity. Here we show that the inhibitor localizes to the Golgi, where it specifically interacts with Dbs-130. Inhibition of endogenous Dbs-130 activity is associated with reduced levels of activated Cdc42, enlarged Golgi, and resistance to Brefeldin A-mediated Golgi dispersal, suggesting a role for Dbs in vesicle transport. Cells treated with the inhibitor exhibit normal protein transport from the ER to the Golgi, but are defective in transport from the Golgi to the plasma membrane. Inhibition of Dbs-130 in MDA-MB-231 human breast tumor cells limits motility in both transwell and wound healing assays, but appears to have no effect on the organization of the microtubule cytoskeleton. The reduced motility is associated with a failure to reorient the Golgi toward the leading edge. This is consistent with the Golgi localization, and suggests that the Dbs-130 regulates aspects of the secretory pathway that are required to support cell polarization during directed migration.