Competition between homodimerization and cholesterol binding to the C99 domain of the amyloid precursor protein.
Competition between homodimerization and cholesterol binding to the C99 domain of the amyloid precursor protein.
复制标题
DOI：
10.1021/bi400735x
复制
发表时间：
2013-07-30
期刊：
影响因子：
2.9
通讯作者：
Sanders, Charles R.
中科院分区：
文献类型：
--
作者：
Song, Yuanli;Hustedt, Eric J.;Brandon, Suzanne;Sanders, Charles R.
淀粉样前体蛋白（APP）的99个残基的跨膜C-末端结构域（C99，也称为β-CTF）是全长APP的β-分泌酶切割的产物和γ-分泌酶切割的底物。后者裂解释放与阿尔茨海默病密切相关的淀粉样蛋白-β多肽。C99被认为形成同二聚体;然而，有利于二聚化的自由能先前没有被定量。最近还证明胆固醇在双胞中与单体C99形成1：1复合物。在此，使用电子顺磁共振（EPR）和福斯特共振能量转移（FRET）方法在双层脂质囊泡中测量了同二聚体和胆固醇与C99结合的亲和力。同源二聚化和胆固醇结合被认为是竞争性过程，其集中在跨膜G700 XXXG 704 XXXG 709甘氨酸拉链基序和相邻的Gly 709上。观察到的胆固醇结合Kd（Kd = 2.7 ± 0.3 mol%）处于哺乳动物细胞膜中生理胆固醇浓度范围的低端。另一方面，观察到的同二聚化的Kd（Kd = 0.47 ± 0.15摩尔%）可能超过C99的生理浓度范围。这些结果表明，在大多数生理条件下，1：1胆固醇：C99复合物比C99同源二聚体更密集，观察结果与理解C99的γ-分泌酶裂解相关。
The 99 residue transmembrane C-terminal domain (C99, also known as β-CTF) of the amyloid precursor protein (APP) is the product of β-secretase cleavage of full length APP and the substrate for γ-secretase cleavage. The latter cleavage releases the amyloid-β polypeptides that are closely associated with Alzheimer’s disease. C99 is thought to form homodimers; however, the free energy in favor of dimerization has not previously been quantitated. It was also recently documented that cholesterol forms a 1:1 complex with monomeric C99 in bicelles. Here, the affinities for both homodimerization and cholesterol binding to C99 were measured in bilayered lipid vesicles using both electron paramagnetic resonance (EPR) and Förster resonance energy transfer (FRET) methods. Homodimerization and cholesterol binding were seen to be competitive processes, which center on the transmembrane G700XXXG704XXXG709 glycine zipper motif and the adjacent Gly709. The observed Kd for cholesterol binding (Kd = 2.7 ± 0.3 mol%) is on the low end of the physiological cholesterol concentration range in mammalian cell membranes. On the other hand, the observed Kd for homodimerization (Kd = 0.47 ± 0.15 mol%) likely exceeds the physiological concentration range for C99. These results suggest that the 1:1 cholesterol:C99 complex will be more highly populated than C99 homodimers under most physiological conditions, observations that are of relevance to understanding γ-secretase cleavage of C99.
登录
查看更多内容
影响因子：
5.3
作者：
Bulic B;Ness J;Hahn S;Rennhack A;Jumpertz T;Weggen S
通讯作者：
Weggen S
影响因子：
4.8
作者：
Cervantes, S;Saura, CA;Marfany, G
通讯作者：
Marfany, G
影响因子：
4.8
作者：
Clarke, Earl E.;Churcher, Ian;Beher, Dirk
通讯作者：
Beher, Dirk
影响因子：
2.9
作者：
Fraering, PC;Ye, WJ;Wolfe, MS
通讯作者：
Wolfe, MS
影响因子：
4.8
作者：
Gralle, Matthias;Botelho, Michelle Gralle;Wouters, Fred S.
通讯作者：
Wouters, Fred S.