Dynamic, temperature-sensitive association of 125-i-nerve growth factor in vitro with ganglionic and non-ganglionic cells from embryonic chick.
125-I-NGF was found to associate with embryonic chick dorsal root ganglia (DRG) through two processes. A time-saturable process included the binding of NGF to surface receptors with an apparent affinity constant in the range of 10(-7)M minus 1 and at a level of 4 f moles/mug tissue protein. The second process was time-linear, temperature-sensitive, and included both bound and non-competable NGF. While metabolic inhibitors had little effect, histone and insulin considerably increased the uptake. A comparison of 125-I-NGF and 125-I-peroxidase uptake suggested that the time-linear uptake of 125-I-NGF must include only bound NGF and incubation medium. Sequestration of the proteins taken up was indicated by the lack of release of radiolabeled material at 4 degrees C, even in the presence of native proteins. All these characteristics are consistent with an interpretation that DRG cells can take up NGF and other proteins by a pinocytotic process. Similar NGF binding and uptake properties were found to occur in cells from a variety of other embryonic chick tissues.
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D005727:Ganglia, Spinal / Q000196:embryology* / Q000378:metabolism; D006657:Histones / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism; D010873:Pinocytosis; D011506:Proteins / Q000378:metabolism; D013268:Stimulation, Chemical; D013696:Temperature; D013997:Time Factors
D006657:Histones; D007328:Insulin; D009414:Nerve Growth Factors; D011506:Proteins; D010544:Peroxidases