The initial events in myelin synthesis: orientation of proteolipid protein in the plasma membrane of cultured oligodendrocytes.
The initial events in myelin synthesis: orientation of proteolipid protein in the plasma membrane of cultured oligodendrocytes.
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髓磷脂合成的最初事件：培养的少突胶质细胞质膜中蛋白质蛋白的方向。
DOI：
10.1083/jcb.109.2.717
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发表时间：
1989-08
影响因子：
7.8
通讯作者：
Lazzarini, R A
中科院分区：
文献类型：
--
作者：
Hudson, L D;Friedrich, V L Jr;Behar, T;Dubois-Dalcq, M;Lazzarini, R A
蛋白质脂蛋白(PLP)是中枢神经系统髓鞘中含量最丰富的跨膜蛋白。基于PLP初级序列的计算机预测和对纯化的髓鞘的实验，已经产生了相互矛盾的PLP拓扑模型。我们研究了髓鞘合成的初始事件，包括PLP在质膜中的插入和定位，在没有神经元的情况下培养表达PLP和其他髓鞘特异蛋白的大鼠少突胶质细胞(Dubois-Dalcq，M.，T.Behar，L.Hudson和R.A.Lazzarini)。1986年。J.细胞生物学。102：384-392)。用六种针对PLP的亲水或疏水短序列的抗肽抗体对这些细胞进行染色，以确定这些细胞的主要髓鞘糖脂表面半乳糖苷。这些抗肽抗体中有五个对活的少突胶质细胞进行了特异性染色。在固定和通透性细胞的胞浆中首次检测到PLP后约10d才出现染色，这表明PLP从RER缓慢地转运到细胞表面。胞外表面PLP结构域的存在也被蛋白酶切割和抗体依赖的补体介导的活的少突胶质细胞裂解所证实。我们的结果表明，PLP只有两个跨膜区，并且绝大多数蛋白质，包括它的氨基和羧基末端，位于少突胶质细胞质膜的胞外面。PLP分子的这种排列表明，相对的胞外面PLP分子之间的同亲相互作用可能调节髓鞘中相邻双层的致密。
Proteolipid protein (PLP) is the most abundant transmembrane protein in myelin of the central nervous system. Conflicting models of PLP topology have been generated by computer predictions based on its primary sequence and experiments with purified myelin. We have examined the initial events in myelin synthesis, including the insertion and orientation of PLP in the plasma membrane, in rat oligodendrocytes which express PLP and the other myelin-specific proteins when cultured without neurons (Dubois-Dalcq, M., T. Behar, L. Hudson, and R. A. Lazzarini. 1986. J. Cell Biol. 102:384-392). These cells, identified by the presence of surface galactocerebroside, the major myelin glycolipid, were stained with six anti-peptide antibodies directed against hydrophilic or short hydrophobic sequences of PLP. Five of these anti-peptide antibodies specifically stained living oligodendrocytes. Staining was only seen approximately 10 d after PLP was first detected in the cytoplasm of fixed and permeabilized cells, suggesting that PLP is slowly transported from the RER to the cell surface. The presence of PLP domains on the extracellular surface was also confirmed by cleavage of such domains with proteases and by antibody-dependent complement-mediated lysis of living oligodendrocytes. Our results indicate that PLP has only two transmembrane domains and that the great majority of the protein, including its amino and carboxy termini, is located on the extracellular face of the oligodendrocyte plasma membrane. This disposition of the PLP molecule suggests that homophilic interactions between PLP molecules of apposed extracellular faces may mediate compaction of adjacent bilayers in the myelin sheath.