Microtubule-associated protein 1B is a component of cortical Lewy bodies and binds α-synuclein filaments
Microtubule-associated protein 1B is a component of cortical Lewy bodies and binds α-synuclein filaments
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DOI：
10.1074/jbc.m000099200
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发表时间：
2000-07-14
影响因子：
4.8
通讯作者：
Gai, WP
中科院分区：
文献类型：
--
作者：
Jensen, PH;Islam, K;Gai, WP
路易体是帕金森病和路易体痴呆的神经病理学标志，由 α-突触核蛋白丝和其他不太明确的蛋白质组成。与 α-突触核蛋白相互作用的路易体蛋白的表征可能有助于深入了解路易体形成的机制。双重免疫荧光标记和共聚焦显微镜显示，大约 80% 的皮质路易体含有与 α-突触核蛋白重叠的微管相关蛋白 1B (MAP-1B)。使用免疫磁技术从因路易体痴呆而死亡的患者的脑组织中分离出路易体。通过聚丙烯酰胺凝胶电泳解析路易体蛋白。免疫印迹证实纯化的路易体中存在 MAP-1B 和 α-突触核蛋白。直接结合研究揭示了 MAP-1B 和 α-突触核蛋白之间存在高亲和力相互作用（IC50，类似于 20 nM）。 MAP-1B 结合位点被定位到 α-突触核蛋白 C 末端的最后 45 个氨基酸。 MAP-1B 还结合体外组装的 α-突触核蛋白原纤维。因此，MAP-1B 可能通过其与单体和纤维状 α-突触核蛋白的相互作用参与路易体的发病机制。
Lewy bodies, neuropathological hallmarks of Parkinson's disease and dementia with Lewy bodies, comprise alpha-synuclein filaments and other less defined proteins. Characterization of Lewy body proteins that interact with alpha-synuclein may provide insight into the mechanism of Lewy body formation. Double immunofluorescence labeling and confocal microscopy revealed approximately 80% of cortical Lewy bodies contained microtubule-associated protein 1B (MAP-1B) that overlapped with alpha-synuclein. Lewy bodies were isolated using an immunomagnetic technique from brain tissue of patients dying with dementia with Lewy bodies. Lewy body proteins were resolved by polyacrylamide gel electrophoresis. Immunoblotting confirmed the presence of MAP-1B and alpha-synuclein in purified Lewy bodies. Direct binding studies revealed a high affinity interaction (IC,, similar to 20 nM) between MAP-1B and alpha-synuclein. The MAP-1B-binding sites were mapped to the last 45 amino acids of the alpha-synuclein C terminus. MAP-1B also bound in vitro assembled alpha-synuclein fibrils. Thus, MAP-1B may be involved in the pathogenesis of Lewy bodies via its interaction with monomeric and fibrillar alpha-synuclein.