Tyrosine phosphorylation at a site highly conserved in the L1 family of cell adhesion molecules abolishes ankyrin binding and increases lateral mobility of neurofascin.
Tyrosine phosphorylation at a site highly conserved in the L1 family of cell adhesion molecules abolishes ankyrin binding and increases lateral mobility of neurofascin.
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DOI：
10.1083/jcb.137.3.703
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发表时间：
1997-05-05
期刊：
影响因子：
--
通讯作者：
Bennett V
中科院分区：
文献类型：
--
作者：
Garver TD;Ren Q;Tuvia S;Bennett V
本文提供了锚蛋白结合细胞粘附分子 L1 家族成员是蛋白酪氨酸激酶和磷酸酶底物的证据，确定了细胞质结构域中高度保守的FigQY酪氨酸作为磷酸化的主要位点，并证明了FIGQY酪氨酸的磷酸化消除了锚蛋白结合 活动。神经母细胞瘤细胞中表达的神经成束蛋白在 NGF 或 bFGF 激活酪氨酸激酶或用钒酸盐或去磷他汀灭活酪氨酸磷酸酶后会发生酪氨酸磷酸化。此外，神经成束蛋白和相关分子 Nr-CAM 在大鼠大脑中以发育调节模式酪氨酸磷酸化。 FigQY 序列存在于神经细胞粘附分子 L1 家族所有成员的细胞质结构域中。通过内源性锚蛋白的免疫共沉淀和体外锚蛋白结合测定确定，FIGQY 酪氨酸的磷酸化会消除锚蛋白结合。光漂白后荧光恢复的测量表明，FIGQY 酪氨酸的磷酸化也增加了神经母细胞瘤细胞中表达的神经成束蛋白的横向移动性，其程度与去除细胞质结构域相同。因此，锚蛋白结合似乎调节神经成束蛋白的动态行为，并且是响应外部信号的酪氨酸磷酸化调节的目标。这些发现表明，FIGQY 位点的酪氨酸磷酸化代表了一种高度保守的机制，整个 L1 相关细胞粘附分子都使用该机制来调节与血影蛋白骨架的锚蛋白依赖性连接。
This paper presents evidence that a member of the L1 family of ankyrin-binding cell adhesion molecules is a substrate for protein tyrosine kinase(s) and phosphatase(s), identifies the highly conserved FIGQY tyrosine in the cytoplasmic domain as the principal site of phosphorylation, and demonstrates that phosphorylation of the FIGQY tyrosine abolishes ankyrin-binding activity. Neurofascin expressed in neuroblastoma cells is subject to tyrosine phosphorylation after activation of tyrosine kinases by NGF or bFGF or inactivation of tyrosine phosphatases with vanadate or dephostatin. Furthermore, both neurofascin and the related molecule Nr-CAM are tyrosine phosphorylated in a developmentally regulated pattern in rat brain. The FIGQY sequence is present in the cytoplasmic domains of all members of the L1 family of neural cell adhesion molecules. Phosphorylation of the FIGQY tyrosine abolishes ankyrin binding, as determined by coimmunoprecipitation of endogenous ankyrin and in vitro ankyrin-binding assays. Measurements of fluorescence recovery after photobleaching demonstrate that phosphorylation of the FIGQY tyrosine also increases lateral mobility of neurofascin expressed in neuroblastoma cells to the same extent as removal of the cytoplasmic domain. Ankyrin binding, therefore, appears to regulate the dynamic behavior of neurofascin and is the target for regulation by tyrosine phosphorylation in response to external signals. These findings suggest that tyrosine phosphorylation at the FIGQY site represents a highly conserved mechanism, used by the entire class of L1-related cell adhesion molecules, for regulation of ankyrin-dependent connections to the spectrin skeleton.