SNAP23 Regulates Endothelial Exocytosis of von Willebrand Factor
Fig 6
SNAP23 interacts with endothelial exocytic machinery.
(A) SNAP23 co-sediments with STX4, VAMP3 and VAMP8 as analyzed by sucrose density gradient fractionation. HUVEC lysates were ultracentrifuged through a 5%–40% discontinuous sucrose gradient, and then the gradient was aliquoted into 17 fractions and analyzed by SDS-PAGE (T, total proteins in the lysate; P, pellet after fractionation). β-actin was used as control for fraction separation. Representative of 3 separate experiments. (B) SNAP23 co-precipitates with STX4, VAMP3 and VAMP8. HUVEC were stimulated with serum-free medium only (Rest), or 10 μM histamine, or 10 μM Ca2+ ionophore A23187 for 30 min; and cell lysates were immunoprecipitated with antibody to SNAP23 or isotype IgG. The precipitants were probed with antibody to STX4, VAMP3 and VAMP8. Input represents 5% total protein. Representative of 3 similar experiments. SNAP23 co-precipitates with STX4, VAMP3, and VAMP8.