GLEPP1, a renal glomerular epithelial cell (podocyte) membrane protein-tyrosine phosphatase. Identification, molecular cloning, and characterization in rabbit.
GLEPP1, a renal glomerular epithelial cell (podocyte) membrane protein-tyrosine phosphatase. Identification, molecular cloning, and characterization in rabbit.
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发表时间：
1994-08
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通讯作者：
P. Thomas;Bryan L. Wharram;M. Goyal;J. Wiggins;L. Holzman;R. Wiggins
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作者：
P. Thomas;Bryan L. Wharram;M. Goyal;J. Wiggins;L. Holzman;R. Wiggins
足细胞是特化的上皮细胞，具有精致的交错状足突，覆盖在肾小球毛细血管的外基底膜表面。它们部分地负责肾小球的特殊电荷和大小滤过特性。为了更好地了解影响肾小球滤过器的疾病过程，我们使用单克隆抗体策略寻找对足细胞具有相对特异性的蛋白质。第一个被鉴定的这种蛋白（指定为肾小球上皮蛋白1 (GLEPP1)）是一种膜蛋白酪氨酸磷酸酶（PTPase），它具有一个大的胞外结构域，包含8个纤维连接蛋白iii型重复序列，一个疏水跨膜段和一个PTPase结构域。GLEPP1 PTPase结构域与另外两个单结构域跨膜PTPase （PTP β和果蝇中枢神经系统PTP10D）具有同源性。这种同源性包括PTPase结构域的2个半胱氨酸，而不存在于细胞内或串联结构域膜PTPase中。GLEPP1 PTPase蛋白分布于足细胞足突本身。RNase保护实验显示GLEPP1 mRNA也存在于脑组织中。与T细胞的CD45 PTPase类似，我们预计该受体可能通过调节足细胞蛋白的酪氨酸磷酸化，在维持足突结构和/或功能中发挥作用。
Podocytes are specialized epithelial cells with delicate interdigitating foot processes which cover the exterior basement membrane surface of the glomerular capillary. They are in part responsible for the extraordinary charge and size filtration characteristics of the glomerulus. To better understand disease processes affecting the glomerular filter, we searched for proteins with relative specificity to the podocyte using a monoclonal antibody strategy. The first such protein characterized (designated glomerular epithelial protein 1 (GLEPP1)) is a membrane protein-tyrosine phosphatase (PTPase) with a large extracellular domain containing eight fibronectin type III-like repeats, a hydrophobic transmembrane segment, and a single PTPase domain. The GLEPP1 PTPase domain shows homology with two other single domain transmembrane PTPases (PTP beta and Drosophila central nervous system PTP10D). This homology includes 2 cysteines in the PTPase domain not present in intracellular or tandem domain membrane PTPases. GLEPP1 PTPase protein is distributed to the podocyte foot processes themselves. RNase protection assay shows that GLEPP1 mRNA is also present in brain. By analogy with the CD45 PTPase of T cells, we expect that this receptor might play a role in maintaining foot process structure and/or function by regulating tyrosine phosphorylation of podocyte proteins.