PDF(Pubmed)
Abstract：
The early phases of clathrin mediated endocytosis are organized through a highly complex interaction network mediated by clathrin associated sorting proteins (CLASPs) that comprise long intrinsically disordered regions (IDRs). AP180 is a CLASP exclusively expressed in neurons and comprises a long IDR of around 600 residues, whose function remains partially elusive. Using NMR spectroscopy, we discovered an extended and strong interaction site within AP180 with the major adaptor protein AP2, and describe its binding dynamics at atomic resolution. We find that the 70 residue-long site determines the overall interaction between AP180 and AP2 in a dynamic equilibrium between its bound and unbound states, while weaker binding sites contribute to the overall affinity at much higher concentrations of AP2. Our data suggest that this particular interaction site might play a central role in recruitment of adaptors to the clathrin coated pit, whereas more transient and promiscuous interactions allow reshaping of the interaction network until cargo uptake inside a coated vesicle.
摘要：
网格蛋白介导的内吞作用的早期阶段是通过由网格蛋白相关分选蛋白（CLASPs）介导的高度复杂的相互作用网络组织的，该蛋白包含长的内在无序区域（IDR）。AP180是仅在神经元中表达的CLASP，包含约600个残基的长IDR，其功能仍然部分难以捉摸。使用NMR光谱，我们在AP180中发现了一个与主要衔接蛋白AP2的扩展和强相互作用位点，并以原子分辨率描述了其结合动力学。我们发现70个残基长的位点决定了AP180和AP2之间的整体相互作用，在其结合状态和未结合状态之间的动态平衡中，而较弱的结合位点有助于在高得多的AP2浓度下的总体亲和力。我们的数据表明，这个特殊的相互作用位点可能在向网格蛋白涂层的坑招募适配器中起着核心作用。而更多的短暂和混杂的相互作用允许相互作用网络的重塑，直到货物吸收到涂层囊泡内。
