Download MendeleyCCDC32 collaborates with the membrane to assemble the AP-2 clathrin adaptor complex.
Sloan, D.E., Matthews, A.E., Yanagisawa, H., Tedamrongwanish, T., Cannon, K., Simmons, J., Chappell, G., Nicely, N.I., Berlow, R., Kikkawa, M., Baker, R.W.(2026) Sci Adv 12: eaeb2377-eaeb2377
- PubMed: 42234739 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1126/sciadv.aeb2377
- Primary Citation Related Structures:
9PPP, 9PUE, 9PWA, 9PWB, 9PWC - PubMed Abstract:
Assembly of adaptor protein complex 2 (AP-2), the primary cargo adaptor in clathrin-mediated endocytosis, is regulated by the chaperones alpha- and gamma-adaptin binding protein (AAGAB) and coiled-coil domain-containing protein 32 (CCDC32), whose deletion causes loss of all AP-2 subunits in vivo. Here, we describe the molecular mechanism of CCDC32-mediated AP-2 assembly. CCDC32 interacts with the appendage domain of the AP-2 α subunit with high affinity, using the same binding site as canonical endocytic regulators in addition to a previously unidentified, yet highly conserved pocket on α. CCDC32 contains cargo sorting motifs normally found in transmembrane cargo and binds to AP-2 heterodimers using canonical cargo-binding sites. In addition, two amphipathic helices in CCDC32 bind to the α/σ2 heterodimer. Unexpectedly, in solution, CCDC32 prevents complex assembly and actively disassembles AP-2 tetramers. Inhibition requires the amphipathic helices of CCDC32, which also mediate binding to phosphatidylinositol 4,5-bisphosphate (PIP 2 )-containing membranes. The presence of PIP 2 -containing membrane stabilizes the final stages of assembly. We propose that the membrane acts as a molecular switch to release inhibitory interactions, allowing for full complex assembly to proceed.
- Department of Biochemistry and Biophysics, UNC Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
Organizational Affiliation:
