Li X J, Snyder S H
Johns Hopkins University School of Medicine, Department of Neuroscience, Baltimore, Maryland 21205, USA.
J Biol Chem. 1995 Jul 28;270(30):17674-9. doi: 10.1074/jbc.270.30.17674.
Salivary secretions modulate taste perception. Taste buds in the circumvallate and foliate papillae are bathed in secretions of unique lingual salivary glands, von Ebner's glands (VEG). We have identified a rat cDNA encoding a novel protein of 1290 amino acids, Ebnerin, that is specifically expressed in VEG and released onto the tongue surface along the apical region of taste buds in the clefts of circumvallate papillae. Ebnerin possesses a putative single transmembrane domain at the C terminus with 17 amino acids in the cytoplasmic area. The extracellular region of Ebnerin contains a number of repeated domains with homology to the scavenger receptor cysteine-rich domain and to a repeated domain of bone morphogenetic protein-I and other related proteins. Western blot analysis reveals that Ebnerin exists in particulate and soluble forms in VEG and is present in secretions from VEG. In situ hybridization and immunohistochemistry demonstrate that Ebnerin is located in secretory duct epithelial cells of VEG and is released onto the tongue surface along the apical region of taste buds in the clefts of circumvallate papillae. The unique structure and localization of Ebnerin suggest that it may function as a binding protein in saliva for the regulation of taste sensation.
唾液分泌调节味觉感知。轮廓乳头和叶状乳头中的味蕾浸泡在独特的舌唾液腺——埃伯纳氏腺（VEG）的分泌物中。我们鉴定出一种大鼠cDNA，其编码一种由1290个氨基酸组成的新型蛋白质——埃伯纳蛋白，该蛋白在VEG中特异性表达，并沿着轮廓乳头裂隙中味蕾的顶端区域释放到舌表面。埃伯纳蛋白在C末端具有一个推定的单跨膜结构域，胞质区域有17个氨基酸。埃伯纳蛋白的细胞外区域包含多个重复结构域，与富含半胱氨酸的清道夫受体结构域以及骨形态发生蛋白-I和其他相关蛋白的重复结构域具有同源性。蛋白质印迹分析表明，埃伯纳蛋白以颗粒形式和可溶形式存在于VEG中，并存在于VEG的分泌物中。原位杂交和免疫组织化学表明，埃伯纳蛋白位于VEG的分泌导管上皮细胞中，并沿着轮廓乳头裂隙中味蕾的顶端区域释放到舌表面。埃伯纳蛋白独特的结构和定位表明，它可能作为唾液中的一种结合蛋白来调节味觉。
