Cell surface presenilin-1 participates in the γ-secretase-like proteolysis of notch
Cell surface presenilin-1 participates in the γ-secretase-like proteolysis of notch
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DOI：
10.1074/jbc.274.51.36801
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发表时间：
1999-12-17
影响因子：
4.8
通讯作者：
Goate, AM
中科院分区：
文献类型：
--
作者：
Ray, WJ;Yao, M;Goate, AM
早老素-1（PS1）是一种主要定位于内质网的多位膜蛋白，是Notch和β-淀粉样前体蛋白（APP）在其跨膜结构域内有效蛋白水解所必需的。裂解APP（称为γ-分泌酶）的活性具有γ-淀粉酰蛋白酶的特性，并且位于PS1的相邻跨膜结构域中的两个天冬氨酸残基中的任一个的突变抑制APP的γ-分泌酶加工。我们在这里表明，这些天冬氨酸是Notch加工所需的，因为这些残基的突变阻止PS1诱导Notch 1衍生物的γ-分泌酶样蛋白水解。因此，PSI可能在Notch切割中作为一种N-乙酰基蛋白酶或二N-乙酰基蛋白酶辅因子起作用。然而，PSI的ER定位与该假设不一致，因为Notch切割发生在细胞表面附近。使用脉冲追踪和生物素化测定，我们提供的证据表明，PS1结合Notch在ER/高尔基体，然后共同运输到质膜作为一个复杂的。PS1天冬氨酸突变体与野生型PS1在其结合Notch或将其运输至细胞表面的能力方面没有区别，并且不改变Notch的分泌。因此，PS1似乎特异性地在质膜附近的Notch蛋白水解中作为一种N-乙酰基蛋白酶或辅因子起作用。
Presenilin-1 (PS1), a polytopic membrane protein primarily localized to the endoplasmic reticulum, is required for efficient proteolysis of both Notch and beta-amyloid precursor protein (APP) within their transmembrane domains. The activity that cleaves APP (called gamma-secretase) has properties of an aspartyl protease, and mutation of either of the two aspartate residues located in adjacent transmembrane domains of PS1 inhibits gamma-secretase processing of APP. We show here that these aspartates are required for Notch processing, since mutation of these residues prevents PS1 from inducing the gamma-secretase-like proteolysis of a Notch1 derivative. Thus PSI might function in Notch cleavage as an aspartyl protease or di aspartyl protease cofactor. However, the ER localization of PSI is inconsistent with that hypothesis, since Notch cleavage occurs near the cell surface. Using pulse-chase and biotinylation assays, we provide evidence that PS1 binds Notch in the ER/Golgi and is then co-transported to the plasma membrane as a complex. PS1 aspartate mutants were indistinguishable from wild-type PS1 in their ability to bind Notch or traffic with it to the cell surface, and did not alter the secretion of Notch. Thus, PS1 appears to function specifically in Notch proteolysis near the plasma membrane as an aspartyl protease or cofactor.