Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA.
Ring Therapeutics, Inc., Cambridge, MA, USA.
Nat Commun. 2023 Nov 21;14(1):7570. doi: 10.1038/s41467-023-43008-5.
ADP-ribosylation factor 1 (Arf1) interacts with multiple cellular partners and membranes to regulate intracellular traffic, organelle structure and actin dynamics. Defining the dynamic conformational landscape of Arf1 in its active form, when bound to the membrane, is of high functional relevance and key to understanding how Arf1 can alter diverse cellular processes. Through concerted application of nuclear magnetic resonance (NMR), neutron reflectometry (NR) and molecular dynamics (MD) simulations, we show that, while Arf1 is anchored to the membrane through its N-terminal myristoylated amphipathic helix, the G domain explores a large conformational space, existing in a dynamic equilibrium between membrane-associated and membrane-distal conformations. These configurational dynamics expose different interfaces for interaction with effectors. Interaction with the Pleckstrin homology domain of ASAP1, an Arf-GTPase activating protein (ArfGAP), restricts motions of the G domain to lock it in what seems to be a conformation exposing functionally relevant regions.
ADP-核糖基化因子 1（Arf1）与多种细胞伴侣和膜相互作用，以调节细胞内运输、细胞器结构和肌动蛋白动力学。定义 Arf1 在其与膜结合的活性形式下的动态构象景观具有高度的功能相关性，是理解 Arf1 如何改变多种细胞过程的关键。通过核磁共振（NMR）、中子反射测量（NR）和分子动力学（MD）模拟的协同应用，我们表明，虽然 Arf1 通过其 N 端豆蔻酰化的两亲螺旋锚定在膜上，但 G 结构域探索了一个很大的构象空间，在膜相关和膜远端构象之间处于动态平衡。这些构象动力学暴露出与效应物相互作用的不同界面。与 Arf-GTP 酶激活蛋白（ArfGAP）ASAP1 的 Pleckstrin 同源结构域的相互作用限制了 G 结构域的运动，将其锁定在似乎暴露了功能相关区域的构象中。
