Fig. 3.

Biochemical characterization of cell-surface BDNF receptors on cells expressing wild-type (trkB.FL, trkB.T1, trkB.T2) and mutant (trkBΔ435 andtrkBΔ423) trkB receptors in clonal, stably transfected L-cells: ¹²⁵I-BDNF cross-linking. Transfected and nontransfected control cells were treated with ¹²⁵I-BDNF, cross-linked with EDAC, and lysed with Triton X-100 containing buffer. Then the lysate was enriched for trkB receptors by wheat germ agglutinin chromatography, fractionated by SDS-PAGE, and visualized by fluorography. Exposure times were 8 hr for trkB.T1 andtrkBΔ435 transfected cells, 3 d fortrkBΔ423 transfected cells, and 2 weeks fortrkB.T2 and trkB.FL transfected cells and for nontransfected control cells. (The x-ray film was not preflashed, which exaggerates the differences between stronger and weaker signals.)