The nonhelical tail domain of keratin 14 promotes filament bundling and enhances the mechanical properties of keratin intermediate filaments in vitro
The nonhelical tail domain of keratin 14 promotes filament bundling and enhances the mechanical properties of keratin intermediate filaments in vitro
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DOI：
10.1083/jcb.200104063
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发表时间：
2001-11-26
影响因子：
7.8
通讯作者：
Coulombe, PA
中科院分区：
文献类型：
--
作者：
Bousquet, O;Ma, LL;Coulombe, PA
角蛋白丝由 I 型和 II 型序列的共聚产生，并形成全细胞质网络，为上皮细胞提供重要的机械支撑。角蛋白 5 和 14 在复层上皮的基底细胞中成对表达，它们以成束的丝状阵列形式出现。在体外，K5-K14 丝束可以在没有交联剂的情况下被诱导，并且表现出增强的机械应变抵抗力。 K5 和无尾 K14 的共聚物（其中非螺旋尾结构域已被去除）或 K5 和 K19（一种具有短尾结构域的 I 型角蛋白）的共聚物不表现出此特性。纯化的 K14 尾部结构域在体外特异性结合角蛋白丝（kD 类似于 2 muM）。当在培养细胞中瞬时表达时，K14 尾部结构域与内源性角蛋白丝结合。在酵母双杂交筛选中利用K14尾部结构域作为诱饵从皮肤cDNA文库中提取I型角蛋白序列。这些数据表明，K14 的尾部结构域有助于 K5-K14 丝自组织成大束的能力，在体外表现出增强的机械弹性。
Keratin filaments arise from the copolymerization of type I and II sequences, and form a pancytoplasmic network that provides vital mechanical support to epithelial cells. Keratins 5 and 14 are expressed as a pair in basal cells of stratified epithelia, where they occur as bundled arrays of filaments. In vitro, bundles of K5-K14 filaments can be induced in the absence of cross-linkers, and exhibit enhanced resistance to mechanical strain. This property is not exhibited by copolymers of K5 and tailless K14, in which the nonhelical tail domain has been removed, or copolymers of K5 and K19, a type I keratin featuring a short tail domain. The purified K14 tail domain binds keratin filaments in vitro with specificity (kD similar to2 muM). When transiently expressed in cultured cells, the K14 tail domain associates with endogenous keratin filaments. Utilization of the K14 tail domain as a bait in a yeast two-hybrid screen pu I Is out type I keratin sequences from a skin cDNA library. These data suggest that the tail domain of K14 contributes to the ability of K5-K14 filaments to self-organize into large bundles showing enhanced mechanical resilience in vitro.