NCKAP1 coordinates focal adhesion and adherens junction dynamics in endothelial barrier maintenance and angiogenesis

Vascular maintenance relies on a delicate balance between cell-cell and cell-matrix interactions. Both undergo dynamic remodeling through actin cytoskeletal rearrangements. A key mechanism driving these processes is the branched actin networks mediated by the Arp2/3 complex and promoted by the WAVE regulatory complex. However, the contribution of WRC to endothelial barrier maintenance and vascular expansion remains incompletely understood. Here, we show that knockdown of NCKAP1 disrupts WRC and impairs lamellipodia-based protrusions in ECs. This defect suppresses paxillin phosphorylation and delays endothelial barrier formation. Nonetheless, despite the barrier integrity being preserved in fully formed endothelial monolayers, actin dynamics at intercellular junctions are inhibited, and consequently restrain angiogenesis. Moreover, our study also revealed a potential role of NCKAP1 in angiogenic signal transduction through suppression of FAK-paxillin signaling. Our findings identify WRC as a direct regulator of FAs and underscore its essential role in coordinating endothelial barrier function and responsiveness to angiogenic cues.