Moore E E, Kuestner R E, Conklin D C, Whitmore T E, Downey W, Buddle M M, Adams R L, Bell L A, Thompson D L, Wolf A, Chen L, Stamm M R, Grant F J, Lok S, Ren H, De Jongh K S
ZymoGenetics, Inc., Seattle, WA, USA.
Horm Metab Res. 1999 Jul;31(7):406-14. doi: 10.1055/s-2007-978764.
Stanniocalcin (STC) is a hormone that was originally identified in fish, where it inhibits calcium uptake by the gills and gut and stimulates phosphate adsorption by the kidney. Recently, two mammalian homologues of stanniocalcin were identified. The first (STC1) shows 61% identity to the fish stanniocalcins and appears to have a function similar to that of the fish stanniocalcins. The second homologue (STC2) is 30-38% identical to the fish stanniocalcins, and is characterized by unique cysteine and histidine motifs that are not found in the other stanniocalcins. We purified both the native hamster and recombinant human STC2 proteins and obtained a partial amino acid sequence of the hamster protein. Both proteins behave as a disulfide bonded homodimer, which undergoes post-translational modification(s). The STC2 gene was localized to human chromosome 5q35. Northern blot analysis revealed that the primary site of human STC2 production is the pancreas, and immunostaining localized the STC2 protein to a subpopulation of cells in the islet. Double immunostaining for STC2 and either insulin or glucagon revealed that STC2 protein is found in the alpha cells, but not the beta cells. We speculate that STC2 may play a role in glucose homeostasis.
鲽源钙调蛋白（STC）是一种最初在鱼类中发现的激素，它能抑制鳃和肠道对钙的摄取，并刺激肾脏对磷酸盐的吸收。最近，人们发现了两种鲽源钙调蛋白的哺乳动物同源物。第一种（STC1）与鱼类鲽源钙调蛋白有61%的同源性，其功能似乎与鱼类鲽源钙调蛋白相似。第二种同源物（STC2）与鱼类鲽源钙调蛋白有30%-38%的同源性，其特征是具有独特的半胱氨酸和组氨酸基序，这在其他鲽源钙调蛋白中未发现。我们纯化了天然仓鼠和重组人STC2蛋白，并获得了仓鼠蛋白的部分氨基酸序列。这两种蛋白均表现为二硫键连接的同型二聚体，且会经历翻译后修饰。STC2基因定位于人类染色体5q35。Northern印迹分析显示，人类STC2产生的主要部位是胰腺，免疫染色将STC2蛋白定位到胰岛中的一个细胞亚群。对STC2与胰岛素或胰高血糖素进行双重免疫染色显示，STC2蛋白存在于α细胞中，而不存在于β细胞中。我们推测STC2可能在葡萄糖稳态中发挥作用。
