PDCD4 and Patent ductus arteriosus: Comprehensive phosphoproteomic quantification of reciprocally engaged PDA cells (Figures 5A–5C and S6A; Data S1) revealed upregulation of several AKT substrates (e.g., BAD [pS136], PDCD4 [pS457], CHSP1 [pS53], AKTS1 [T247], and GSK-3α [pS21]).