Splicing variations in the ligand-binding domain of ApoER2 results in functional differences in the binding properties to Reelin
Splicing variations in the ligand-binding domain of ApoER2 results in functional differences in the binding properties to Reelin
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DOI：
10.1016/j.neures.2008.12.009
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发表时间：
2009-04-01
影响因子：
2.9
通讯作者：
Hattori, Mitsuharu
中科院分区：
文献类型：
--
作者：
Hibi, Terumasa;Mizutani, Masato;Hattori, Mitsuharu
Reelin 通过与载脂蛋白 E 受体 2 (ApoER2) 和极低密度脂蛋白受体结合，在大脑形成中发挥关键作用。 Reelin 的几种亚型和片段是通过选择性剪接和蛋白水解切割产生的。此外，ApoER2 的两个剪接变体已被识别，即 LA1237 和 LA12378，它们的配体结合 A 型 (LA) 重复序列数量不同。在这里，我们定量研究了 Reelin 的各种亚型/片段与 ApoER2 剪接变体之间的亲和力。 ApoER2-LA1237 与 Reelin 中心片段的结合比与带有 Reelin 重复序列 8 (RR8) 的片段的结合要强。 ApoER2-LA12378 与所有不含 C 末端区域的 Reelin 片段的结合程度相当。这些发现表明 ApoER2 的 LA8 和 RR8 干扰 Reelin 中心片段和 ApoER2 之间的相互作用。使用仅识别ApoER2-LA12378的单克隆抗体，我们发现ApoER2的这种变体在发育过程中的大脑皮质壁和小脑的内部颗粒细胞中表达。原代培养的皮层神经元不表达 ApoER2-LA12378，Reelin 片段的信号激活程度与其对 ApoER2-LA1237 的亲和力密切相关。因此，Reelin的蛋白水解切割和ApoER2的选择性剪接可能参与了Reelin信号传导的精细调节。 (C) 2009 Elsevier Ireland Ltd 和日本神经科学学会。版权所有。
Reelin plays critical roles in brain formation by binding to apolipoprotein E receptor 2 (ApoER2) and very low-density lipoprotein receptor. Several isoforms and fragments of Reelin are generated by alternative splicing and proteolytic cleavage. In addition, two splice variants of ApoER2 have been recognized, namely, LA1237 and LA12378, that differ in the number of ligand-binding type A (LA) repeats.Here, we quantitatively investigated the affinity between various isoforms/fragments of Reelin and the ApoER2 splice variants. ApoER2-LA1237 bound rather strongly to the Reelin central fragment than to the fragment bearing Reelin repeat 8 (RR8). ApoER2-LA12378 bound comparably to all Reelin fragments without the C-terminal region. These findings suggest that LA8 of ApoER2 and RR8 interfere with the interaction between the Reelin central fragment and ApoER2. Using a monoclonal antibody that only recognizes ApoER2-LA12378, we found that this variant of ApoER2 was expressed in the cerebral cortical wall and in the internal granule cells of the cerebellum during development. Primary-cultured cortical neurons did not express ApoER2-LA12378, and the extent of signal activation by Reelin fragments was well correlated with their affinity for ApoER2-LA1237. Therefore, proteolytic cleavage of Reelin and alternative splicing of ApoER2 may be involved in the fine regulation of Reelin signaling. (C) 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.