Role of the AP2 beta-appendage hub in recruiting partners for clathrin-coated vesicle assembly.
Role of the AP2 beta-appendage hub in recruiting partners for clathrin-coated vesicle assembly.
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AP2 Beta-Apperdage Hub在招募网格蛋白包被囊泡组件的伙伴中的作用。
DOI：
10.1371/journal.pbio.0040262
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发表时间：
2006-09
期刊：
影响因子：
9.8
通讯作者：
McMahon, Harvey T
中科院分区：
文献类型：
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作者：
Schmid, Eva M;Ford, Marijn G J;Burtey, Anne;Praefcke, Gerrit J K;Peak-Chew, Sew-Yeu;Mills, Ian G;Benmerah, Alexandre;McMahon, Harvey T
接头蛋白复合体2、α和β-附件结构域作为辅助蛋白网络的枢纽，参与分子筛蛋白包膜囊泡的形成。我们通过质谱学鉴定了一大批β-附件相互作用装置。它们与β-附属物上的两个不同的配体相互作用位点(“顶”和“侧”位点)相互作用，结合不同于先前在α-附属物上发现的基序。我们解决了β-附件的结构，从辅助蛋白EPS15结合到侧面位置，与顶部结合的辅助货物适配器β-arrestin的肽。我们发现，辅助蛋白可以同时与多个附件结合，允许这些附件协同增强配体亲和力，这在体外似乎是不可逆的。我们现在提出，随着涂层凹坑的成熟，与β-附件相互作用的笼蛋白在体内通过自我聚合实现配体置换。这改变了相互作用的环境，从液相亲和力驱动的相互作用，到固相稳定性驱动的相互作用(“成熟度”)。因此，只与附属物相互作用的辅助蛋白被置换到包被的纹孔中尚未聚合的区域。然而，β-arrestin(非视觉arrestin)和常染色体隐性高胆固醇血症蛋白等直接与笼状蛋白相互作用的蛋白质将与其相互作用的受体保留在包被的凹坑中。笼蛋白包裹的囊泡的形成依赖于由接头蛋白复合体2(AP2)组装的辅助蛋白，在内吞作用中起重要作用。在这里，质谱学和结晶鉴定了被AP2的Sβ-Appendage为此招募的蛋白质。
Adaptor protein complex 2 α and β-appendage domains act as hubs for the assembly of accessory protein networks involved in clathrin-coated vesicle formation. We identify a large repertoire of β-appendage interactors by mass spectrometry. These interact with two distinct ligand interaction sites on the β-appendage (the “top” and “side” sites) that bind motifs distinct from those previously identified on the α-appendage. We solved the structure of the β-appendage with a peptide from the accessory protein Eps15 bound to the side site and with a peptide from the accessory cargo adaptor β-arrestin bound to the top site. We show that accessory proteins can bind simultaneously to multiple appendages, allowing these to cooperate in enhancing ligand avidities that appear to be irreversible in vitro. We now propose that clathrin, which interacts with the β-appendage, achieves ligand displacement in vivo by self-polymerisation as the coated pit matures. This changes the interaction environment from liquid-phase, affinity-driven interactions, to interactions driven by solid-phase stability (“matricity”). Accessory proteins that interact solely with the appendages are thereby displaced to areas of the coated pit where clathrin has not yet polymerised. However, proteins such as β-arrestin (non-visual arrestin) and autosomal recessive hypercholesterolemia protein, which have direct clathrin interactions, will remain in the coated pits with their interacting receptors. Formation of clathrin-coated vesicles, important in endocytosis, relies on accessory proteins assembled by adaptor protein complex 2 (AP2). Here, mass spectrometry and crystallization identifies proteins recruited by AP2's β-appendage for this purpose.