The par-tiam1 complex controls persistent migration by stabilizing microtubule-dependent front-rear polarity
The par-tiam1 complex controls persistent migration by stabilizing microtubule-dependent front-rear polarity
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DOI：
10.1016/j.cub.2007.08.035
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发表时间：
2007-10-09
期刊：
影响因子：
9.2
通讯作者：
Collard, John G.
中科院分区：
文献类型：
--
作者：
Pegtel, D. Michiel;Ellenbroek, Saskia I. J.;Collard, John G.
背景：细胞极性的建立和维持对许多生物功能至关重要，并受保守蛋白复合物的调节。由Par3、Par6和PKC zeta组成的Par极性复合物与tiam1介导的Rac信号一起，控制着接触上皮细胞的顶基细胞极性。在这里，我们验证了Par复合体与Tiam1一起在自由迁移的角质形成细胞持续迁移过程中控制“前后”极性的假设。结果：野生型（WT）表皮角质形成细胞缺乏细胞间接触，具有稳定的前后极化和持续的迁移。相比之下，Tiam1缺陷（Tiam1 KO）和（si） par3缺失的角质形成细胞通常是不极化的，并且由于前后极性的存在时间很短而随机迁移。免疫沉淀实验表明，在迁移的角质形成细胞中，Tiam1与Par3和PKC zeta相关。此外，Par3、PKC zeta和Tiam1蛋白在极化角化细胞的前缘富集。Tiam1 KO角质形成细胞向生长因子的趋化迁移受到损害，因此趋化迁移与WT相似。WT角质形成细胞中Par3的缺失或PKC zeta信号的阻断会损害趋化性，但对Tiam1 KO细胞没有额外的影响。partiam1功能受损的角质形成细胞的迁移和形态缺陷与具有药理学不稳定微管（MTs）的细胞非常相似。事实上，PKC zeta抑制剂处理的Tiam1 KO角质形成细胞和WT细胞中的mt是不稳定的，因此对定向而非随机迁移产生负面影响。结论：我们得出的结论是，Par-Tiam1复合物稳定了非接触迁移细胞的前后极化，从而刺激了持续和趋化迁移，而在接触角化细胞中，相同的复合物控制了持久的顶基极性的建立。这些发现强调了Par极性复合物的显著灵活性，根据生物学背景，它控制着不同形式的细胞极性。
Background: The establishment and maintenance of cell polarity is crucial for many biological functions and is regulated by conserved protein complexes. The Par polarity complex consisting of Par3, Par6, and PKC zeta, in conjunction with Tiam1-mediated Rac signaling, controls apical-basal cell polarity in contacting epithelial cells. Here we tested the hypothesis that the Par complex, in conjunction with Tiam1, controls "front-rear" polarity during the persistent migration of freely migrating keratinocytes.Results: Wild-type (WT) epidermal keratinocytes lacking cell-cell contacts are stably front-rear polarized and migrate persistently. In contrast, Tiam1-deficient (Tiam1 KO) and (si)Par3-depleted keratinocytes are generally unpolarized and migrate randomly because front-rear polarity is short lived. Immunoprecipitation experiments show that in migrating keratinocytes, Tiam1 associates with Par3 and PKC zeta. Moreover, Par3, PKC zeta, and Tiam1 proteins are enriched at the leading edges of polarized keratinocytes. Tiam1 KO keratinocytes are impaired in chemotactic migration toward growth factors, whereaes haptotactic migration is similar to WT. Par3 depletion or the blocking of PKC zeta signaling in WT keratinocytes impairs chemotaxis but has no additional effect on Tiam1 KO cells. The migratory and morphological defects in keratinocytes with impaired Par-Tiam1 function closely resemble cells with pharmacologically destabilized microtubules (MTs). Indeed, MTs in Tiam1 KO keratinocytes and WT cells treated with a PKC zeta inhibitor are unstable, thereby negatively influencing directional but not random migration.Conclusions: We conclude that the Par-Tiam1 complex stabilizes front-rear polarization of noncontacting migratory cells, thereby stimulating persistent and chemotactic migration, whereas in contacting keratinocytes, the same complex controls the establishment of long-lasting apical-basal polarity. These findings underscore a remarkable flexibility of the Par polarity complex that, depending on the biological context, controls distinct forms of cellular polarity.