“…Two transmembrane proteins contribute to NGF binding and the initiation of signal transduction in NGF-responsive neuronal cells. The low affinity NGF receptor, LNGFR or gp75, was the first receptor protein component characterized (Grob et al, 1985), has an appropriate tissue distribution in the nervous system (Taniuchi et al, 1986;Large et al, 1989), and binds NGF with a Kd around 1 nM (Vale & Shooter, 1985). The LNGFR has a relatively small intracellular domain Radeke et al, 1987) and appears to be necessary but not sufficient to mediate full biologReprint requests to: Kenneth E. Neet, Department of Biological Chemistry, UHSKhicago Medical School, 3333 Green Bay Rd., North Chicago, Illinois 60064 Present address: Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201. ical response (Hempstead et al, 1989;Matsushima & Bogenmann, 1990;Pleasure et al, 1990;Yan et al, 1991).…”