Jensen P J, Wheelock M J
Department of Dermatology, University of Pennsylvania, Philadelphia 19104-6142.
Exp Cell Res. 1992 Sep;202(1):190-8. doi: 10.1016/0014-4827(92)90419-9.
In keratinocyte culture, the cellular distribution of many adhesion markers and the organization of intercellular junctions are controlled by the calcium ion concentration of the medium. We show in the present study that urokinase plasminogen activator (uPA) localization in the human keratinocyte is similarly dependent upon calcium concentration. At 30 microM calcium, uPA is present throughout the cell, often with a perinuclear concentration. Upon calcium elevation to 1.0 mM, uPA is concentrated along the cell-cell borders, where it colocalizes (at the light microscope level) with E-cadherin. Blocking antibody to E-cadherin delays the calcium-induced redistribution of uPA, in a manner very similar to the previously observed delay in redistribution of several adhesion-related markers, including vinculin, desmoplakin, and beta 1 integrin. These data suggest a link between the redistribution of uPA to the cell-cell borders and the calcium-induced organization of intercellular junctions in the human keratinocyte. The presence of uPA along the intercellular borders suggests that this enzyme may be involved in regulation of epidermal adhesion through proteolysis.
在角质形成细胞培养中，许多黏附标记物的细胞分布以及细胞间连接的组织受培养基中钙离子浓度的控制。我们在本研究中表明，尿激酶型纤溶酶原激活剂（uPA）在人角质形成细胞中的定位同样依赖于钙浓度。在30微摩尔钙离子浓度下，uPA存在于整个细胞中，通常在核周聚集。当钙离子浓度升高到1.0毫摩尔时，uPA沿着细胞 - 细胞边界聚集，在那里它（在光学显微镜水平）与E - 钙黏蛋白共定位。针对E - 钙黏蛋白的阻断抗体以一种与先前观察到的几种黏附相关标记物（包括纽蛋白、桥粒斑蛋白和β1整合素）重新分布延迟非常相似的方式，延迟了钙离子诱导的uPA重新分布。这些数据表明uPA向细胞 - 细胞边界的重新分布与人角质形成细胞中钙离子诱导的细胞间连接组织之间存在联系。uPA在细胞间边界的存在表明该酶可能通过蛋白水解参与表皮黏附的调节。
