DN-PACS-2 prevents degradation of newly synthesized CD31 by K5. (A) E-DMVECs were transduced with the indicated recombinant adenoviruses for 24 hours, and cell-surface expression of MHC I or CD31 was analyzed by flow cytometry (unshaded). Untreated cells stained for CD31 or MHC I are shown for comparison (shaded). Note that both CD31 and MHC I are down-regulated by K5, but only CD31 surface expression is restored upon cotransduction of DN-PACS-2. (B) Top panel shows immunoprecipitation of CD31 from E-DMVEC transduced with the indicated adenoviruses and metabolically labeled for 45 minutes (P) followed by a 3-hour chase. Bottom panel shows one-fourth of each sample immunoprecipitated using lamin A/C antibody as a loading control.