Interaction of CD36 with Syk, VEGFR2, and their downstream signaling proteins. HDMECs were lysed either in 1% Brij 99 or 1% Triton X-100, and an equal amount of protein was used for immunoprecipitation. (A) Anti-CD36 (lane 2) and nonimmune IgG (lane 1) immunoprecipitants were Western blotted with Abs to Syk, Vav, and p85 PI3K. The p85 subunit of PI3K was detected in 1% Brij 99, while Syk and Vav were present in 1% Triton X-100 immunoprecipitants (supplemental Figure 1B). (B) Triton X-100–solubilized lysates were immunoprecipitated with anti-Syk (lane 2) and nonimmune IgG (lane 1) Abs (supplemental Figure 1B). The nitrocellulose membrane was probed with an anti-CD36 Ab. (C) In reciprocal immunoprecipitations, HDMEC cells were lysed in 1% Brij 99 and immunoprecipitated with anti-VEGFR-2 (lane 2) and nonimmune IgG (lane 1) Abs, and immunoprecipitants were probed with either anti-Syk (left) or anti-CD36 (right) Abs (supplemental Figure 3). (D-E) To determine whether Triton X-100 can disrupt the association of Syk and CD36 with VEGFR-2, HDMECs were lysed in either 1% Brij 99 or 1% Triton X-100 and immunoprecipitated with anti-VEGFR-2 (lane 2) and nonimmune IgG (lane 1) Abs. Immunoprecipitants were probed with anti-Syk, anti-CD36, and anti-VEGFR-2 Abs, as indicated.