Figure 1.

VEGF-B binds selectively to VEGFR-1. (A) Metabolically labeled VEGF₁₆₅, mVEGF-B₁₆₇, mVEGF-B₁₈₆, or VEGF-C was precipitated by using receptor-Ig fusion proteins bound to protein A-Sepharose, or immunoprecipitated with specific antibodies as described in the text. Approximately 50 ng of each receptor-Ig was used. The precipitates were analyzed by SDS/PAGE in reducing conditions. (B) mVEGF-B₁₆₇ and mVEGF-B₁₈₆ were bound to VEGFR-1-Ig as above in the absence (−) or presence (+) of 2 μg of recombinant hVEGF₁₆₅. (C) Displacement of ¹²⁵I-hVEGF₁₆₅ from NIH 3T3/VEGFR-1 cells by mVEGF-B₁₈₆ or mVEGF₁₆₄. (D) Displacement of ¹²⁵I-hVEGF₁₆₅ from NIH 3T3/VEGFR-1 cells by conditioned medium containing equal amounts of mVEGF-B_Ex1–5 wild-type (WT) or mutant forms. Mean ± SD of triplicate samples in one of three independent experiment is shown.