Keratin-dependent regulation of desmosome composition and actin organization

桥粒组成和肌动蛋白组织的角蛋白依赖性调节

• 批准号: 273121961
• 负责人: Professor Dr. Thomas Magin
• 金额: --
• 依托单位: Professur für Zell- und Entwicklungsbiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/273121961?language=en
• 关键词: Keratin; dependent; regulation; desmosome; composition

The mammalian epidermis is a multilayered epithelium that protects the body against physical and chemical insults by virtue of keratinocytes that are held together by desmosomes connected to cytoskeletal keratins. Epidermal differentiation, wound healing and barrier formation require constant remodeling of desmosomes and the keratin cytoskeleton to transform cuboidal keratinocytes into flat corneocytes for barrier formation and into migratory keratinocytes to promote wound repair. This remodeling requires differentiation-specific expression of isotypes of keratins and desmosomal proteins. It is regulated by growth factors and mechanical force and requires cross-talk to the actin cytoskeleton. Little is known about mechanisms by which keratin isotypes regulate desmosome composition and adhesive strength and how these changes are coordinated with the actin cytoskeleton and adherens junctions.During the first funding period, we have found that keratin isotype composition serves as a regulator of desmosome composition and adhesive strength. Whereas K14 expression led to stable desmosomes with high levels of Dsg1 and low C-terminal phosphorylation of desmoplakin, expression of K17 reduced Dsg1 at mRNA and protein levels and increased Dsg3, in addition to increasing C-terminal desmoplakin phosphorylation. Collectively, these changes weakened intercellular adhesion. Further, K17 expression coincided with decreased cortical actin organization in keratinocytes, similar to observations in the skin of keratin-deficient mice. In the skin, altered actin organization coincided with failure of keratinocytes to flatten during barrier formation. In the second funding period, we want to test the hypothesis that keratin isotypes regulate desmosome composition and adhesive strength through direct protein interactions with desmoplakin and plakophilin, and indirectly, through posttranslational protein modifications. To that end, we will focus on phosphorylation of select protein domains. Further, we want to examine whether keratins, via Dsg1, affect cortical actin organization and thereby mediate keratinocyte flattening during epidermal differentiation. We will test our hypothesis by exploiting our panel of mouse keratinocytes re-expressing keratin isotypes and variants, in addition to transgenic mice.We expect that our project provides an understanding how members of the keratin family regulate intercellular adhesion through interaction with desmosomal proteins.

哺乳动物表皮是一种多层上皮，其通过角质形成细胞保护身体免受物理和化学损伤，所述角质形成细胞通过与细胞骨架角蛋白连接的桥粒保持在一起。表皮分化、伤口愈合和屏障形成需要桥粒和角蛋白细胞骨架的不断重塑，以将立方形角质形成细胞转化为平坦的角质形成细胞以形成屏障，并转化为迁移性角质形成细胞以促进伤口修复。这种重塑需要角蛋白和桥粒蛋白的同种型的分化特异性表达。它受生长因子和机械力的调节，需要与肌动蛋白细胞骨架进行交互。角蛋白同种型调节桥粒组成和粘附强度的机制以及这些变化如何与肌动蛋白细胞骨架和adherens junctions.During第一个资金期间，我们发现角蛋白同种型组成作为桥粒组成和粘附强度的调节剂。而K14的表达导致稳定的桥粒与高水平的Dsg 1和低的C-末端桥斑蛋白磷酸化，K17的表达减少Dsg 1在mRNA和蛋白质水平和增加Dsg 3，除了增加C-末端桥斑蛋白磷酸化。总的来说，这些变化削弱了细胞间粘附。此外，K17的表达与角质形成细胞中皮质肌动蛋白组织的减少相一致，这与角蛋白缺陷小鼠皮肤中的观察结果相似。在皮肤中，肌动蛋白组织的改变与角质形成细胞在屏障形成过程中扁平化的失败相吻合。 在第二个资助期，我们要测试的假设，角蛋白同种型调节桥粒组成和粘附强度，通过直接的蛋白质相互作用与桥粒斑蛋白和plakophilin，间接地，通过翻译后蛋白质修饰。为此，我们将重点关注选择蛋白质结构域的磷酸化。此外，我们要检查是否角蛋白，通过Dsg 1，影响皮质肌动蛋白的组织，从而介导表皮分化过程中的角质形成细胞扁平化。我们将测试我们的假设，利用我们的小组的小鼠角质形成细胞重新表达角蛋白同种型和变体，除了转基因mice.We期望我们的项目提供了一个了解如何角蛋白家族的成员调节细胞间粘附通过相互作用与桥粒蛋白。