Download MendeleyStructural basis for the dynamic conformations of AP-4 and its association with ARF1.
Wang, Y., Li, W., Qiu, Y., Wu, S., Hong, L., Zhao, Y., Feng, W.(2026) Nat Commun 17
- PubMed: 41565640 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41467-026-68679-8
- Primary Citation Related Structures:
9U9I, 9U9J, 9U9R, 9U9S - PubMed Abstract:
Among the distinct adaptor protein (AP) complexes, AP-4 primarily functions as a non-clathrin-coated vesicle machinery essential for intracellular membrane trafficking. ARF1 is a master regulator of AP-4 membrane recruitment, but the underlying mechanism remains elusive. Here, we present the cryo-EM structures of soluble AP-4 and the AP-4/ARF1 complex. Unexpectedly, AP-4 adopts a dynamic equilibrium between closed and open conformations, caused by loose contacts between its medium subunit and central core. ARF1 binding induces only subtle changes in AP-4, which retains its conformational equilibrium. Mutations at the AP-4/ARF1 interface disrupt complex formation and impair ARF1-dependent membrane recruitment. Efficient membrane recruitment of AP-4 likely requires the synergistic engagement of ARF1 and cargoes. Disrupting the conformational flexibility of AP-4 interferes with this synergistic effect and compromises AP-4-mediated membrane trafficking. Our findings may redefine AP-4 as a conformationally dynamic complex modulated by cooperative interactions, providing insights into neurodevelopmental disorders associated with AP-4 dysfunction.
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, China.
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