Tyrosine autophosphorylation controls the catalytic and signaling activities of the
neurotrophin receptors, the Trks. To analyze the regulation of distinct tyrosine sites, we
generated a panel of antibodies that report the phosphorylation state of individual tyrosines
within the Trk cytoplasmic domain. Using pheochromocytoma-derived cell lines, we show
that individual tyrosines within the nerve growth factor receptor TrkA are phosphorylated in a
non-coordinate fashion following receptor activation. The non-coordinate response of these …