FUNCTIONAL ANALYSIS OF PLAKIN FAMILY PROTEINS

Plakin家族蛋白具有芳香族细胞连接蛋白，包括桥粒连结蛋白、凝集素、大疱性类天疱疮抗原1(BPAG1)、包膜蛋白、周斑蛋白和海藻蛋白，它们具有氨基末端球状结构域、无中心结构域和羧基末端藻球结构域，其中氨基末端球状结构域介导与质膜的相互作用，羧基末端藻球结构域与中间丝结合。我们发现，在培养体系中，稳定转Envoplakin的小鼠角质形成细胞具有显著的角化/分化能力。这导致我们提出，Plakin家族蛋白可以介导角质形成细胞的角化/分化。结果：1.Envoplakin/Periplakin稳定表达的小鼠角质形成细胞在三维培养体系中显示出明显的角化/分化。2.在表皮恶性肿瘤中，plakin家族蛋白的定位和转谷氨酰胺酶的原位活性明显受到干扰，而在良性肿瘤中则无此现象。

Plakin family proteins have aroleascytolinker proteins, which includes desmoplakin, plectin, Bullous pemphigoid antigen 1(BPAG1), envoplakin, periplakin andepiplakin They have an amino-terminal globular domain, acentrarod domain and a carboxy-terminalglobular domain The an amino-terminal globular domain mediating the interaction with the plasma membrane and the carboxy-terminalglobular domain associating with intermediate filaments. We find that the envoplakin stably transfected mouse keratinocytes showed remarkable keratinisation/differentiation in culture system. This led us to propose that the plakin family proteins can mediates keratinisation/differentiation of keratinocyte. The aim of our experiments was to carryout amoredetailed study about the relationship of plakin family proteins and epidermal keratinocyte Keratinisation/differentiation.Results : 1.Envoplakin/Periplakin stably transfected mouse keratinocytes showed remarkable keratinisation/differentiation in 3-D keratinocyte culture system. About the other plakins, series of the experiment is now on the way.2.In the epidermal malignant tumors, the localization of the plakin family proteins and in situ activity of transglutaminase were remarkably disturbed, but in the benign tumors were not.