Membrane localization is critical for activation of the PICK1BAR domain
Membrane localization is critical for activation of the PICK1BAR domain
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DOI：
10.1111/j.1600-0854.2008.00761.x
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发表时间：
2008-08-01
期刊：
影响因子：
4.5
通讯作者：
Gether, Ulrik
中科院分区：
文献类型：
--
作者：
Madsen, Kenneth L.;Eriksen, Jacob;Gether, Ulrik
PSD-95/Discs-large/ZO-1同源（PDZ）结构域蛋白，与C激酶1（PICK 1）相互作用的蛋白质，含有一个C-末端Bin/两栖physin/Rvs（BAR）结构域，介导弯曲膜的识别;然而，控制该结构域活性的分子机制知之甚少。与N-末端PDZ结构域对BAR结构域的负调控一致，PICK 1均匀地分布在细胞质中，而PDZ结构域的截短导致BAR结构域依赖性重新分布到与再循环内体隔室的标记物共定位的簇。在PDZ和BAR结构域之间的接头中短的推定α-螺旋片段的截短和PICK 1与跨膜PDZ配体（包括α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体GluR 2亚基）共表达时，都观察到类似的聚类，GluR 2 C-末端转移至单跨膜蛋白Tac或多巴胺转运蛋白C-末端转移至Tac。与此相反，转移的GluR 2 C-末端的青色荧光蛋白，胞质蛋白，没有引起BAR结构域依赖的聚类。相反，通过引入N-末端豆蔻酰化位点将PICK 1定位于膜产生BAR结构域依赖性但不依赖于配体的PICK 1聚类。数据支持在不存在PDZ配体的情况下，PICK 1 BAR结构域通过PDZ结构域依赖性和接头依赖性机制被抑制。此外，他们认为BAR结构域的膜结合能力的暴露不是配体与PDZ结构域本身结合的结果，而是PICK 1募集到膜隔室的结果。
The PSD-95/Discs-large/ZO-1 homology (PDZ) domain protein, protein interacting with C kinase 1 (PICK1) contains a C-terminal Bin/amphiphysin/Rvs (BAR) domain mediating recognition of curved membranes; however, the molecular mechanisms controlling the activity of this domain are poorly understood. In agreement with negative regulation of the BAR domain by the N-terminal PDZ domain, PICK1 distributed evenly in the cytoplasm, whereas truncation of the PDZ domain caused BAR domain-dependent redistribution to clusters colocalizing with markers of recycling endosomal compartments. A similar clustering was observed both upon truncation of a short putative alpha-helical segment in the linker between the PDZ and the BAR domains and upon coexpression of PICK1 with a transmembrane PDZ ligand, including the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR2 subunit, the GluR2 C-terminus transferred to the single transmembrane protein Tac or the dopamine transporter C-terminus transferred to Tac. In contrast, transfer of the GluR2 C-terminus to cyan fluorescent protein, a cytosolic protein, did not elicit BAR domain-dependent clustering. Instead, localizing PICK1 to the membrane by introducing an N-terminal myristoylation site produced BAR domain-dependent, but ligand-independent, PICK1 clustering. The data support that in the absence of PDZ ligand, the PICK1 BAR domain is inhibited through a PDZ domain-dependent and linker-dependent mechanism. Moreover, they suggest that unmasking of the BAR domain's membrane-binding capacity is not a consequence of ligand binding to the PDZ domain per se but results from, and coincides with, recruitment of PICK1 to a membrane compartment.