Phosphorylation-dependent structure and dynamics of caveolin-1 8S complex.

Caveolin-1 (Cav-1) is a membrane-associated scaffolding protein essential for lipid regulation, cellular signaling, and caveolae formation. Phosphorylation at tyrosine 14 (Y14) of Cav-1 plays a pivotal role in modulating its functional dynamics, but the structural consequences of this modification remain unexplored. This site belongs to the N-terminal tail, which is unresolved in the recent cryoelectron microscopy structures of the Cav-1 8S complexes. In this work, we used AlphaFold 3 (AF3) to generate a full-length model of the human Cav-1 8S complex and its phosphorylated form and performed molecular dynamics simulations of both complexes embedded in the plasma membrane. Inclusion of the N-terminal tail in the AF3-predicted models significantly enhances protein-membrane interactions, highlighting the membrane-binding role of the N-terminal tail. Our results show that the Y14 phosphorylation induces significant conformational changes to the N-terminal tail structure with enhanced inter-protomer hydrogen bonding resulting in an altered conformational state. The results provide mechanistic insights into how phosphorylation may act as a molecular switch that regulates Cav-1's structural behavior, membrane affinity, and caveolae biogenesis.