The nerve growth factor receptor, TrkA, is essential for the survival and differentiation of neurons in the central and peripheral nervous systems. To understand the molecular principles underlying this differentiation step, we employed a yeast two-hybrid screening protocol using human TrkA as bait. We isolated c-Abl as a TrkA-interacting protein, in addition to known proteins such as phospholipase Cγ and SH2-B. This interaction was confirmed by an in vitro binding assay using glutathione S-tranferase–Abl fusion protein. Furthermore, we show here that c-Abl binds to phosphotyrosine residue(s) in the kinase activation loop of TrkA.
