FIG. 1.

Schematic diagrams of oncogenic Trk, TrkA, and ΔTrkA. Oncogenic Trk contains sequences of tropomyosin in place of most of the extracellular domain of TrkA. ΔTrkA contains an in-frame 75-amino-acid deletion of the extracellular domain of TrkA. The deletion is the result of a loss of 225 nucleotides from the trkA gene (nucleotides 1030 to 1254). Nucleotide numbering is based on the TrkA GenBank submission (accession number M23102). Nucleotides shown in lowercase type are not present in the ΔTrkA cDNA. The triangles above TrkA indicate sites of glycosylation. Four glycosylation sites (solid triangles) are deleted in ΔTrkA. The signal peptide, transmembrane domain, and tyrosine kinase domain in TrkA are indicated.