Edwards A M, Arquint M, Braun P E, Roder J C, Dunn R J, Pawson T, Bell J C
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Mol Cell Biol. 1988 Jun;8(6):2655-8. doi: 10.1128/mcb.8.6.2655-2658.1988.
Myelin-associated glycoprotein (MAG) has been implicated in the mediation of interactions between oligodendrocytes and neurons during the development of the myelin sheath. Here we show that MAG is phosphorylated in intact myelinating mouse brain primarily at serine residues and to a lesser extent at threonine and tyrosine residues. In vivo, only the larger of the two developmentally regulated MAG isoforms is phosphorylated. MAG can be phosphorylated at tyrosine by the v-fps and v-src protein-tyrosine kinases in vitro and by a kinase endogenous to myelin membrane preparations. MAG phosphorylated in myelin membranes in vitro also contains phosphoserine and phosphothreonine. These observations suggest that phosphorylation of MAG is physiologically significant in regulating oligodendrocyte-neuron interactions.
髓鞘相关糖蛋白（MAG）被认为在髓鞘形成过程中参与少突胶质细胞与神经元之间相互作用的介导。在此我们表明，在完整的有髓鞘形成的小鼠大脑中，MAG主要在丝氨酸残基处磷酸化，在苏氨酸和酪氨酸残基处磷酸化的程度较低。在体内，两种受发育调控的MAG同工型中只有较大的一种被磷酸化。在体外，MAG可被v-fps和v-src蛋白酪氨酸激酶磷酸化酪氨酸，也可被髓鞘膜制剂中的内源性激酶磷酸化。体外在髓鞘膜中磷酸化的MAG也含有磷酸丝氨酸和磷酸苏氨酸。这些观察结果表明，MAG的磷酸化在调节少突胶质细胞-神经元相互作用中具有生理意义。
