Role of laminin terminal globular domains in basement membrane assembly
Role of laminin terminal globular domains in basement membrane assembly
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DOI：
10.1074/jbc.m702963200
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发表时间：
2007-07-20
影响因子：
4.8
通讯作者：
Yurchenco, Peter D.
中科院分区：
文献类型：
--
作者：
Mckee, Karen K.;Harrison, David;Yurchenco, Peter D.
层粘连蛋白通过其N-和C-末端球状结构域的相互作用促进基底膜组装。为了进一步分析这一过程，重组层粘连蛋白-111缺失和点突变的异源三聚体产生的重组表达和评估其自组装的能力，与巢蛋白-1和IV型胶原蛋白，并形成细胞外基质培养的雪旺细胞通过免疫荧光和电子显微镜。与具有缺失的α 1-、β 1-或γ 1-LN结构域或具有重复的β 1-或α 1-LN结构域的层粘连蛋白相反，野生型层粘连蛋白和没有LG结构域的层粘连蛋白聚合。层粘连蛋白与LN和LG结构域的完整互补物在细胞表面上积累，基本上高于那些缺乏LN或LG结构域的层粘连蛋白，形成致密层。IV型胶原在细胞表面上的积累被发现需要层粘连蛋白与层粘连蛋白LN结构域，巢蛋白-1，和层粘连蛋白中的巢蛋白结合位点的存在下产生的单独的贡献。总的来说，这些数据支持这样的假设：基底膜组装取决于层粘连蛋白通过形成α-、β-和γ-LN结构域复合物以及LG介导的细胞表面锚定进行自组装。此外，IV型胶原募集到层粘连蛋白细胞外基质似乎是通过巢蛋白桥介导的，与层粘连蛋白的直接相互作用产生的贡献较小。
Laminins contribute to basement membrane assembly through interactions of their N- and C-terminal globular domains. To further analyze this process, recombinant laminin-111 heterotrimers with deletions and point mutations were generated by recombinant expression and evaluated for their ability to self-assemble, interact with nidogen-1 and type IV collagen, and form extracellular matrices on cultured Schwann cells by immunofluorescence and electron microscopy. Wild-type laminin and laminin without LG domains polymerized in contrast to laminins with deleted alpha 1-, beta 1-, or gamma 1-LN domains or with duplicated beta 1- or alpha 1-LN domains. Laminins with a full complement of LN and LG domains accumulated on cell surfaces substantially above those lacking either LN or LG domains and formed a lamina densa. Accumulation of type IV collagen onto the cell surface was found to require laminin with separate contributions arising from the presence of laminin LN domains, nidogen-1, and the nidogen-binding site in laminin. Collectively, the data support the hypothesis that basement membrane assembly depends on laminin self-assembly through formation of alpha-, beta-, and gamma-LN domain complexes and LG-mediated cell surface anchorage. Furthermore, type IV collagen recruitment into the laminin extracellular matrices appears to be mediated through a nidogen bridge with a lesser contribution arising from a direct interaction with laminin.