Expression of polypeptide variants of receptor-type protein tyrosine phosphatase beta: the secreted form, phosphacan, increases dramatically during embryonic development and modulates glial cell behavior in vitro.
Expression of polypeptide variants of receptor-type protein tyrosine phosphatase beta: the secreted form, phosphacan, increases dramatically during embryonic development and modulates glial cell behavior in vitro.
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受体型蛋白酪氨酸磷酸酶β的多肽变体的表达：分泌形式磷酸聚糖在胚胎发育过程中急剧增加，并在体外调节神经胶质细胞的行为。
DOI：
10.1002/(sici)1097-4547(19960315)43:6
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发表时间：
1996
影响因子：
4.2
通讯作者：
Grumet,M
中科院分区：
文献类型：
--
作者：
Sakurai,T;Friedlander,DR;Grumet,M
神经胶质细胞表达一种称为rpppβ的受体类型蛋白酪氨酸磷酸酶的三种剪接变体。两种受体形式在较大的细胞外域中不同。第三种是一种被称为磷酸多糖的分泌型蛋白多糖，它缺乏细胞质磷酸酶结构域。我们现在已经通过免疫印迹在大鼠C6胶质瘤细胞和脑中鉴定出与这三种形式的rptpβ相对应的蛋白质。在C6胶质瘤细胞中，短受体形式比全长受体更为普遍。磷酸多糖在大鼠脑中的含量远高于这两种受体形式，在胚胎发育过程中其表达逐渐增加，而受体形式仅表现出温和的变化。与被检测为蛋白多糖的长型和磷酸多糖不同，缺少大的选择性剪接结构域的短受体形式没有被检测到是硫酸软骨素蛋白多糖。我们最近发现，磷酸聚糖可以与神经元-胶质细胞黏附分子Ng-CAM结合，现在我们报道了表达RPTPβ的胶质细胞在涂有Ng-CAM的底物上黏附和延长突起。然而，在培养一天后，神经胶质细胞收回它们的突起，并经常提起底物。来自神经胶质细胞的条件培养液中含有大量的磷脂聚糖，可抑制胶质细胞与Ng-CAM的黏附，免疫吸附耗尽条件培养液中的磷脂聚糖会降低抑制活性。结果表明，在发育过程中，磷酸多糖显著增加，提示分泌形式的rptpβ可以调节神经胶质细胞的黏附和行为。©1996 Wiley-Liss，Inc.
Glial cells express three splicing variants of a receptor‐type protein tyrosine phosphatase called RPTPβ. Two are receptor forms that differ in a large extracellular domain. The third is a secreted proteoglycan called phosphacan that lacks the cytoplasmic phosphatase domains. We have now identified, by immunoblotting, proteins corresponding to these three forms of RPTPβ in rat C6 glioma cells and brain. The short receptor form is much more prevalent than the full‐length receptor in C6 glioma cells. Phosphacan is much more abundant than either of the receptor forms in rat brain, and its expression increases progressively during embryonic development, while the receptor forms show only moderate changes. In contrast to the long form and phosphacan that were detected as proteoglycans, the short receptor form, lacking the large alternatively spliced domain, was not detected as a chondroitin sulfate proteoglycan. We recently showed that phosphacan binds to the neuron‐glia cell adhesion molecule, Ng‐CAM, and we now report that glia expressing RPTPβ adhere and extend processes on substrates coated with Ng‐CAM. After one day in culture, however, the glia retract their processes and often lift off the substrate. Conditioned medium from glial cells, which contains large amounts of phosphacan, inhibits glial adhesion to Ng‐CAM, and depletion of phosphacan from the conditioned medium by immunoadsorption reduces the inhibitory activity. The results show that phosphacan increases dramatically during development, and indicate that secreted forms of RPTPβ can modulate glial cell adhesion and behavior. © 1996 Wiley‐Liss, Inc.