Type XVII Collagen Regulates Lamellipod Stability, Cell Motility, and Signaling to Rac1 by Targeting Bullous Pemphigoid Antigen 1e to α6β4 Integrin
Type XVII Collagen Regulates Lamellipod Stability, Cell Motility, and Signaling to Rac1 by Targeting Bullous Pemphigoid Antigen 1e to α6β4 Integrin
复制标题
DOI：
10.1074/jbc.m110.203646
复制
发表时间：
2011-07-29
影响因子：
4.8
通讯作者：
Jones, Jonathan C. R.
中科院分区：
文献类型：
--
作者：
Hamill, Kevin J.;Hopkinson, Susan B.;Jones, Jonathan C. R.
Rac 1活性、极性、片状伪足动力学和定向运动性在角质形成细胞中是有缺陷的，其表现为β 4整联蛋白的缺乏或斑蛋白大疱性类天疱疮抗原1 e（BPAG 1 e）的敲低。通过诱导截短形式的β 4整联蛋白的表达，在β 4整联蛋白缺陷细胞中恢复Rac的活性、稳定的片状伪足的形成和定向迁移，所述截短形式的β 4整联蛋白缺乏BPAG 1 e和网蛋白的结合位点。在这些相同的细胞中，BPAG 1 e（截短的β 4整联蛋白）和XVII型胶原（Col XVII）（一种跨膜BPAG 1 e结合蛋白，但不是胶凝蛋白）沿基质附着表面共定位沿着。这一发现提示我们，Col XVII介导BPAG 1 e和含有截短的β 4亚基的α 6 β 4整联蛋白的结合，并支持定向迁移。为了测试这些可能性，我们敲低了表达全长和截短的β 4整联蛋白的角质形成细胞中的Col XVII表达。Col XVII-敲低的角质形成细胞表现出BPAG 1 e-α 6 β 4整合素相互作用的丧失、板状脂质体稳定性的降低、定向运动性的损害和Rac 1活性的降低。这些缺陷被羧基末端截短的突变Col XVII蛋白质所挽救。总之，我们的研究结果表明，在运动细胞中，Col XVII将BPAG 1 e募集为α 6 β 4整联蛋白，并且是激活信号通路、运动行为和板状伪足稳定性所必需的。
Rac1 activity, polarity, lamellipodial dynamics, and directed motility are defective in keratinocytes exhibiting deficiency in beta 4 integrin or knockdown of the plakin protein Bullous Pemphigoid Antigen 1e (BPAG1e). The activity of Rac, formation of stable lamellipodia, and directed migration are restored in beta 4 integrin-deficient cells by inducing expression of a truncated form of beta 4 integrin, which lacks binding sites for BPAG1e and plectin. In these same cells, BPAG1e, the truncated beta 4 integrin, and type XVII collagen (Col XVII), a transmembrane BPAG1e-binding protein, but not plectin, colocalize along the substratum-attached surface. This finding suggested to us that Col XVII mediates the association of BPAG1e and alpha 6 beta 4 integrin containing the truncated beta 4 subunit and supports directed migration. To test these possibilities, we knocked down Col XVII expression in keratinocytes expressing both full-length and truncated beta 4 integrin proteins. Col XVII-knockdown keratinocytes exhibit a loss in BPAG1e-alpha 6 beta 4 integrin interaction, a reduction in lamellipodial stability, an impairment in directional motility, and a decrease in Rac1 activity. These defects are rescued by a mutant Col XVII protein truncated at its carboxyl terminus. In summary, our results suggest that in motile cells Col XVII recruits BPAG1e to alpha 6 beta 4 integrin and is necessary for activation of signaling pathways, motile behavior, and lamellipodial stability.