Division of Cell Biology I, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands.
Mass Spectrometry/Proteomics Facility, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands.
Biol Open. 2020 Aug 13;9(8):bio054155. doi: 10.1242/bio.054155.
The integrin α6β4 and cytoskeletal adaptor plectin are essential components of type I and type II hemidesmosomes (HDs). We recently identified an alternative type II HD adhesion complex that also contains CD151 and the integrin α3β1. Here, we have taken a BioID proximity labeling approach to define the proximity protein environment for α6β4 in keratinocytes. We identified 37 proteins that interacted with both α6 and β4, while 20 and 78 proteins specifically interacted with the α6 and β4 subunits, respectively. Many of the proximity interactors of α6β4 are components of focal adhesions (FAs) and the cortical microtubule stabilizing complex (CMSC). Though the close association of CMSCs with α6β4 in HDs was confirmed by immunofluorescence analysis, CMSCs have no role in the assembly of HDs. Analysis of the β4 interactome in the presence or absence of CD151 revealed that they are strikingly similar; only 11 different interactors were identified. One of these was the integrin α3β1, which interacted with α6β4 more strongly in the presence of CD151 than in its absence. These findings indicate that CD151 does not significantly contribute to the interactome of α6β4, but suggest a role of CD151 in linking α3β1 and α6β4 together in tetraspanin adhesion structures.
整合素 α6β4 和细胞骨架衔接蛋白 plectin 是 I 型和 II 型半桥粒（HDs）的重要组成部分。我们最近鉴定出一种替代的 II 型 HD 粘附复合物，它还包含 CD151 和整合素 α3β1。在这里，我们采用 BioID 邻近标记方法来定义角质形成细胞中 α6β4 的邻近蛋白环境。我们鉴定出 37 种与 α6 和 β4 相互作用的蛋白质，而 20 种和 78 种蛋白质分别与 α6 和 β4 亚基特异性相互作用。α6β4 的许多邻近相互作用蛋白是粘着斑（FA）和皮质微管稳定复合物（CMSC）的组成部分。尽管免疫荧光分析证实了 CMSC 与 HD 中 α6β4 的紧密关联，但 CMSC 对 HD 的组装没有作用。在存在或不存在 CD151 的情况下分析 β4 相互作用组，发现它们非常相似；仅鉴定出 11 种不同的相互作用蛋白。其中一种是整合素 α3β1，在存在 CD151 的情况下，它与 α6β4 的相互作用比不存在 CD151 时更强。这些发现表明 CD151 对 α6β4 的相互作用组没有显著贡献，但表明 CD151 在将 α3β1 和 α6β4 连接在一起形成四跨膜蛋白粘附结构中的作用。
