Isolation of the cDNA encoding glycoprotein-2 (GP-2), the major zymogen granule membrane protein. Homology to uromodulin/Tamm-Horsfall protein.
Isolation of the cDNA encoding glycoprotein-2 (GP-2), the major zymogen granule membrane protein. Homology to uromodulin/Tamm-Horsfall protein.
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分离编码糖蛋白-2 (GP-2)（主要酶原颗粒膜蛋白）的 cDNA。
DOI：
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发表时间：
1991
影响因子：
4.8
通讯作者：
M. Rindler
中科院分区：
文献类型：
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作者：
T. C. Hoops;M. Rindler
GP-2是一种78 kDa的糖蛋白，是胰腺外分泌物中酶原颗粒膜的主要成分。我们报道了从大鼠胰腺lambda GT-11基因文库中分离到编码GP-2的基因。该基因全长1921个碱基对，有一个开放阅读框，编码530个氨基酸的蛋白质，含有8个潜在的N-糖基化位点。它包括蛋白质的氨基末端，包括信号序列，这是在狗胰腺粗大微体存在下进行的体外转录/翻译实验所证明的，在这些微体中，蛋白质经历了明显的核心糖基化。在羧基末端存在一段疏水的氨基酸，这可能是糖基磷脂酰肌醇(GPI)膜锚连接的信号，正如GP-2所描述的那样。将该基因导入HeLa细胞，表达的蛋白定位于细胞表面，与磷脂酰肌醇特异性磷脂酶C孵育后可释放，证实它是GPI连接的。在GenBank数据库中搜索，发现GP-2的氨基酸序列与人的尿调蛋白/Tamm-Horsfall蛋白(THP)有53%的同源性和85%的相似性，450个氨基酸的延伸包含了GP-2信号序列之后的全部28个半胱氨酸。尿调蛋白/Tamm-Horsfall蛋白是由肾脏合成的一种85 kDa的糖蛋白，除了序列上的相似性外，它还与GP-2有许多相似之处。两者都通过GPI锚定附着在膜上，但也从各自细胞的顶端表面释放出来，随后形成大的聚集体。它们可能共同定义一个新的基因家族。
GP-2, a 78-kDa glycoprotein, is the major component of zymogen granule membranes of the exocrine pancreas. We report the isolation of the cDNA encoding for GP-2 from a rat pancreatic lambda gt-11 cDNA library. The cDNA is 1921 base pairs in length with an open reading frame encoding for a protein of 530 amino acids containing eight potential N-glycosylation sites. It encompasses the amino terminus of the protein including the signal sequence as evidenced by in vitro transcription/translation experiments conducted in the presence of dog pancreas rough microsomes in which the protein underwent apparent core glycosylation. A hydrophobic stretch of amino acids is present at the carboxyl terminus which is likely to serve as a signal for attachment of a glycosyl phosphatidylinositol (GPI) membrane anchor as has been described for GP-2. When the cDNA was introduced into HeLa cells by transfection, the expressed protein was located on the cell surface and could be released by incubation of the cells with phosphatidylinositol-specific phospholipase C, confirming that it is GPI-linked. Upon searching through the GenBank database, the GP-2 amino acid sequence was found to have a 53% identity and 85% similarity to human uromodulin/Tamm-Horsfall protein (THP) over a 450-amino acid stretch that encompassed all 28 cysteines after the signal sequence of GP-2. Uromodulin/Tamm-Horsfall protein, an 85-kDa glycoprotein synthesized by the kidney, shares several characteristics with GP-2 in addition to its sequence similarity. Both are attached to the membrane by a GPI anchor, but are also released from the apical surface of their respective cells and subsequently form large aggregates. Together they may define a new gene family.