CHARACTERIZATION OF AN INTEGRAL MEMBRANE GLYCOPROTEIN ASSOCIATED WITH THE MICROFILAMENTS OF PIG INTESTINAL MICROVILLI
CHARACTERIZATION OF AN INTEGRAL MEMBRANE GLYCOPROTEIN ASSOCIATED WITH THE MICROFILAMENTS OF PIG INTESTINAL MICROVILLI
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DOI：
10.1002/j.1460-2075.1983.tb01446.x
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发表时间：
1983-01-01
期刊：
影响因子：
11.4
通讯作者：
LOUVARD, D
中科院分区：
文献类型：
--
作者：
COUDRIER, E;REGGIO, H;LOUVARD, D
猪小肠微绒毛膜上的一种完整的膜糖蛋白，经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）测得其分子量分别为140-K和200-K。200-K形式可能是140-K种类的前体。使用特异性抗体的电子显微镜免疫化学定位的糖蛋白和其相对于膜双层的拓扑组织进行了测定。Triton X-100处理，溶解大多数其他微绒毛膜糖蛋白从纯化的，封闭的，右侧外囊泡不能有效地提取这种蛋白质。蛋白质可通过用蛋白酶（胰蛋白酶或木瓜蛋白酶）处理或通过在螯合剂和洗涤剂存在下暴露于低离子强度缓冲液而从洗涤剂不溶性残留物中部分溶解。一旦被木瓜蛋白酶或胰蛋白酶溶解，蛋白质在SDS-PAGE上与通过低离子强度提取获得的蛋白质共迁移。然而，由木瓜蛋白酶释放的蛋白质的形式不结合洗涤剂，并表现出亲水性。这些观察结果与140-K蛋白具有将其锚定到微绒毛膜的小疏水结构域一致。140-K糖蛋白在体外与核心细胞骨架残基的110-K蛋白结合。140-K糖蛋白可以是跨膜蛋白，其可以在体内提供与微绒毛细胞骨架的多肽直接或间接结合的附着位点。
An integral membrane glycoprotein of pig intestinal microvilli which exists in 2 polypeptide forms [MW 140-K [kilodalton] and 200-K as measured by SDS[sodium dodecylsulfate]-polyacrylamide gel electrophoresis (SDS-PAGE)] was purified to homogeneity and characterized. The 200-K form is probably a precursor of the 140-K species. The glycoprotein was localized by electron microscope immunochemistry using specific antibodies and its topological organization with respect to the membrane bilayer was determined. Triton X-100 treatments which solubilize most other microvillar membrane glycoproteins from purified, closed, right-side out vesicles do not efficiently extract this protein. The protein can be partially solubilized from the detergent-insoluble residue, either by treatment with proteases (trypsin or papain) or by exposure to low ionic strength buffer in the presence of chelating agents and detergents. Once solubilized by papain or trypsin, the protein comigrates on SDS-PAGE with the protein obtained by low ionic strength extraction. However, the form of the protein released by papain does not bind detergents and exhibits hydrophilic properties. These observations are consistent with the 140-K protein having a small hydrophobic domain that anchors it to the microvillar membrane. The 140-K glycoprotein binds in vitro to a 110-K protein of the core cytoskeleton residue. The 140-K glycoprotein may be a transmembrane protein which may in vivo provide attachment sites for direct or indirect association with polypeptides of the microvillus cytoskeleton.