The moelcular basis of the mechanisums on that the extracellular calcium ions regulate the differentiation of human esopahgeal epithelial cells

细胞外钙离子（Ca^2+）在调节鳞状上皮细胞的分化中是重要的。本研究利用人食管上皮细胞（EECs）的原代培养，通过增加细胞外Ca^<2+>浓度来诱导EECs的分化，试图阐明EECs的分化机制。本研究获得了以下三个新的发现：1）钙结合蛋白S100 P在人内皮细胞中的表达可被Ca^<2+>诱导。S100 P在上皮的基底上层和上几层中被检测到，增殖细胞也位于其中。人食管上皮细胞在分化过程中依次产生不同的S100蛋白，包括S100 A2、S100 A6、S100 P和CAAF 1（S100 A12）; 3）人CAAF 1蛋白以非共价同源二聚体形式存在，Ca^<2+>和Zn^<2+>协同促进寡聚体的自结合，提示S100蛋白在食管上皮细胞分化的特定阶段可能起重要作用。了解钙离子在鳞状上皮细胞中的功能需要分析钙结合蛋白，特别是S100蛋白。

Extracellular calcium ions (Ca^<2+>) are important in regulating the differentiation of squamous epithelial cells. We tried to clarify the mechanisms of the differentiation of human esophageal epithelial cells using the primary culture of human esophageal epithelial cells (EECs), which can be differentiated by increasing the concentration of extracellular Ca^<2+>. And we got three new findings as the below :1) A calcium-binding protein S100P showed a Ca^<2+> inducible expression in human EECs. S100P was detected in vivo in the suprabasal and the upper few layers of the epithelium, in which the proliferating cells were also located. S100P expression is transiently expressed during the early stage of differentiation.2) Human esophageal epithelial cells sequentially produce different S100 proteins, including S100A2, S100A6, S100P and CAAF1 (S100A12) in the process of differentiation.3) Human CAAF1 proteins exist as noncovalent homodimers, and Ca^<2+> and Zn^<2+> synergistically promote the oligomeric self-association.These findings suggest that within esophageal epithelial cells S100 proteins might play important roles in cell differentiation during specific stages. An understanding of calcium function in the squamous epithelial cells will require the analysis of calcium-binding proteins, especially S100 proteins.