Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125, Berlin, Germany.
Université Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France.
Nat Commun. 2024 Jul 13;15(1):5884. doi: 10.1038/s41467-024-50212-4.
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.
网格蛋白介导的内吞作用的早期阶段是通过网格蛋白相关分拣蛋白（CLASPs）介导的高度复杂的相互作用网络组织的，这些蛋白包含长的固有无序区域（IDRs）。AP180 是一种仅在神经元中表达的 CLASP，包含大约 600 个残基的长 IDR，其功能仍部分难以捉摸。使用 NMR 光谱学，我们在 AP180 中发现了一个与主要衔接蛋白 AP2 之间的扩展和强相互作用位点，并在原子分辨率下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，在其结合和非结合状态之间处于动态平衡，而较弱的结合位点在 AP2 的浓度更高时对整体亲和力有贡献。我们的数据表明，这个特殊的相互作用位点可能在衔接蛋白向网格蛋白包被小窝的募集中起核心作用，而更多的瞬时和混杂相互作用允许相互作用网络的重塑，直到包裹在囊泡内的货物被摄取。
