Owh P, da Cruz L A, Ackerley C A, Moscarello M A
Division of Biochemistry, Hospital for Sick Children, Toronto, Ontario/Canada.
Eur J Cell Biol. 1997 Oct;74(2):172-80.
An astrocytoma cell line (HTB-14), expressing high amounts of a CD44 variant compared to other astrocytoma lines was shown to bind myelin basic protein to a greater extent than low expressing lines in a concentration-dependent manner. The CD44 variant expressed by HTB-14 cells was determined to migrate in sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular mass of 100 kDa compared to that from white matter which had a molecular mass of 80 kDa. The most cationic component of myelin basic protein (MBP), (component 1) bound more avidly than the least cationic isomer (component 8). Internalization of MBP was demonstrated by immunogold electron microscopy and was localized to the perinuclear area with some gold particles in the cytoplasm but not near the plasma membrane. Colocalization with glial fibrillary acid protein suggested an interaction between these two molecules. Binding and internalization of MBP was accompanied by an increase in CD44 as determined by quantitation of gold particles and the measurement of CD44 by sandwich enzyme-linked immunosorbent assay. The implication of these studies for the mechanism of demyelination is discussed.
与其他星形细胞瘤细胞系相比，一种表达大量CD44变体的星形细胞瘤细胞系（HTB - 14）被证明比低表达细胞系能以浓度依赖的方式更大量地结合髓鞘碱性蛋白。经测定，HTB - 14细胞表达的CD44变体在十二烷基硫酸钠聚丙烯酰胺凝胶电泳中的迁移分子量为100 kDa，而来自白质的该变体分子量为80 kDa。髓鞘碱性蛋白（MBP）的最具阳离子性的组分（组分1）比阳离子性最弱的异构体（组分8）结合更紧密。免疫金电子显微镜证实了MBP的内化，其定位于核周区域，细胞质中有一些金颗粒，但靠近质膜处没有。与胶质纤维酸性蛋白的共定位表明这两种分子之间存在相互作用。通过金颗粒定量和夹心酶联免疫吸附测定法检测CD44发现，MBP的结合和内化伴随着CD44的增加。本文讨论了这些研究对脱髓鞘机制的意义。
