Constitutive and regulated α-secretase cleavage of Alzheimer's amyloid precursor protein by a disintegrin metalloprotease
Constitutive and regulated α-secretase cleavage of Alzheimer's amyloid precursor protein by a disintegrin metalloprotease
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DOI：
10.1073/pnas.96.7.3922
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发表时间：
1999-03-30
影响因子：
11.1
通讯作者：
Fahrenholz, F
中科院分区：
文献类型：
--
作者：
Lammich, S;Kojro, E;Fahrenholz, F
淀粉样β肽（Aβ）是阿尔茨海默病患者大脑中淀粉样斑块的主要蛋白质成分，是通过淀粉样前体蛋白（APP）的蛋白水解裂解而衍生的。 Aβ序列内推定的α分泌酶对APP的蛋白水解裂解阻止了淀粉样肽的形成，并导致可溶性APPα释放到培养基中。通过在 HEK 293 细胞中过表达解整合素和金属蛋白酶 (ADAM)（分类为 ADAM 10），基础和蛋白激酶 C 刺激的 α 分泌酶活性增加数倍。 ADAM 10 的蛋白水解激活形式通过质膜中的细胞表面生物素化定位，但大部分酶原存在于高尔基体中。这些结果支持了 APP 在细胞表面和沿着分泌途径被裂解的观点。内源性 α 分泌酶活性受到锌结合位点点突变的 ADAM 10 显性失活形式的抑制。使用纯化的 ADAM 10 和 A beta 片段进行的研究证实了正确的 α 分泌酶切割位点，并证明了对底物构象的依赖性。我们的结果证明 ADAM 10 具有 α 分泌酶活性和 APP 蛋白水解加工所需的许多特性。其表达和活性的增加可能有利于阿尔茨海默氏病的治疗。
Amyloid beta peptide (A beta), the principal proteinaceous component of amyloid plaques in brains of Alzheimer's disease patients, is derived by proteolytic cleavage of the amyloid precursor protein (APP). Proteolytic cleavage of APP by a putative alpha-secretase within the A beta sequence precludes the formation of the amyloidogenic peptides and leads to the release of soluble APPs alpha into the medium. By overexpression of a disintegrin and metalloprotease (ADAM), classified as ADAM 10, in HEK 293 cells, basal and protein kinase C-stimulated alpha-secretase activity was increased severalfold. The proteolytically activated form of ADAM 10 was localized by cell surface biotinylation in the plasma membrane, but the majority of the proenzyme was found in the Golgi. These results support the view that APP is cleaved both at the cell surface and along the secretory pathway. Endogenous alpha-secretase activity was inhibited by a dominant negative form of ADAM 10 with a point mutation in the zinc binding site. Studies with purified ADAM 10 and A beta fragments confirm the correct alpha-secretase cleavage site and demonstrate a dependence on the substrate's conformation. Our results provide evidence that ADAM 10 has alpha-secretase activity and many properties expected for the proteolytic processing of APP, Increases of its expression and activity might be beneficial for the treatment of Alzheimer's disease.