Loss of β-PIX inhibits focal adhesion disassembly and promotes keratinocyte motility via myosin light chain activation
Loss of β-PIX inhibits focal adhesion disassembly and promotes keratinocyte motility via myosin light chain activation
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DOI：
10.1242/jcs.196147
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发表时间：
2017-07-15
影响因子：
4
通讯作者：
Jones, Jonathan C. R.
中科院分区：
文献类型：
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作者：
Hiroyasu, Sho;Stimac, Gregory P.;Jones, Jonathan C. R.
在皮肤愈合过程中，角质形成细胞的细胞骨架及其基质粘连，包括局灶性粘连（FA），经历重组。这些变化由小GTP酶及其调节剂协调，包括鸟嘌呤核苷酸交换因子β-PIX（也称为ARHGEF 7）。在成纤维细胞中，β-PIX激活小GTP酶，从而增强迁移。在体外角质形成细胞中，β-PIX定位于FA。为了研究β-PIX功能，我们产生了β-PIX敲低的角质形成细胞。在β-PIX敲低细胞单层的伤口闭合过程中，FA的分解受损，并且它们的数量和大小增加。此外，在β-PIX敲低细胞中，磷酸化肌球蛋白轻链（MLC;也称为MYL 2）不仅存在于伤口前部的细胞前缘中，而且存在于前部之后的细胞中，而MLC激酶（MYLK）的调节剂p21活化激酶2（PAK 2）被错误定位。MYLK的抑制或消耗恢复了β-PIX敲减细胞中的FA分布。由β-PIX敲低细胞产生的牵引力相对于对照细胞中的那些增加，这一结果与单个β-PIX敲低细胞和这种细胞的单层的迁移中的意外增强一致。我们认为靶向β-PIX可能是促进体内伤口上皮形成的一种手段。
During healing of the skin, the cytoskeleton of keratinocytes and their matrix adhesions, including focal adhesions (FAs), undergo reorganization. These changes are coordinated by small GTPases and their regulators, including the guanine nucleotide exchange factor beta-PIX (also known as ARHGEF7). In fibroblasts, beta-PIX activates small GTPases, thereby enhancing migration. In keratinocytes in vitro, beta-PIX localizes to FAs. To study beta-PIX functions, we generated beta-PIX knockdown keratinocytes. During wound closure of beta-PIX knockdown cell monolayers, disassembly of FAs is impaired, and their number and size are increased. In addition, in the beta-PIX knockdown cells, phosphorylated myosin light chain (MLC; also known as MYL2) is present not only in the leading edge of cells at the wound front, but also in the cells following the front, while p21-activated kinase 2 (PAK2), a regulator of MLC kinase (MYLK), is mislocalized. Inhibition or depletion of MYLK restores FA distribution in beta-PIX knockdown cells. Traction forces generated by beta-PIX knockdown cells are increased relative to those in control cells, a result consistent with an unexpected enhancement in the migration of single beta-PIX knockdown cells and monolayers of such cells. We propose that targeting beta-PIX might be a means of promoting epithelialization of wounds in vivo.