Properties of the nerve growth factor receptor. Relationship between receptor structure and affinity.
Microsomal membranes from A875 human melanoma cells contain nerve growth factor receptors (NGF-receptors) which appear to belong to a single class with homogeneous binding properties, as determined by Scatchard plots. NGF-receptors in these membrane preparations are also uniformly highly sensitive to tryptic proteolysis, and 125I-NGF bound to NGF-receptor in these membranes is rapidly dissociated in the presence of a high concentration of unlabeled NGF. However, analysis of 125I-NGF dissociation kinetics indicated that two classes of NGF-receptor were present in these membranes. Thus, NGF-receptors can express either high or low affinity trypsin-sensitive states in addition to the high affinity trypsin resistant NGF-receptor state described previously (Buxser, S. E., Kelleher, D. J., Watson, L., Puma, P., and Johnson, G. L. (1983) J. Biol. Chem. 258, 3741-3749). The high affinity trypsin-sensitive and low affinity trypsin-sensitive states correlate with 200- and 90-kDa 125I-NGF X NGF-receptor complexes observed in photoaffinity cross-linking experiments. The absence of differences in peptide maps generated from the two sizes of NGF-receptor proteins together with structural and binding data strongly indicates that the 200-kDa NGF-receptor protein is a complex, probably a dimer, consisting of two 80-kDa NGF-receptor proteins associated with a single beta-NGF dimeric molecule. A model is proposed which relates structural states of NGF-receptors with specific receptor binding properties. The model provides an alternative explanation for binding phenomena previously attributed to negative cooperativity.
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D000818:Animals; D002460:Cell Line; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D046911:Macromolecular Substances; D008297:Male; D008545:Melanoma / Q000378:metabolism; D051379:Mice; D008861:Microsomes / Q000378:metabolism; D009414:Nerve Growth Factors / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017475:Receptors, Nerve Growth Factor; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism
D008081:Liposomes; D046911:Macromolecular Substances; D009414:Nerve Growth Factors; D011956:Receptors, Cell Surface; D017475:Receptors, Nerve Growth Factor; D014357:Trypsin