An 82-kilodalton membrane protein that inhibits the activity of neurite outgrowth factor

Neurite outgrowth factor (NOF), an extracellular matrix glycoprotein of 700 kilodaltons (kDa), promoted neurite outgrowth from cultured ciliary ganglion (CG) neurons of chicken embryo. A fraction solubilized with Nonidet P-40 of chicken gizzard muscle membranes inhibited the neurite-promoting activity of NOF in a dose-dependent manner, but not that of laminin. Binding of CG neurons to the substratum and their survival were not affected by the extract. The inhibitory activity of the extract was abolished by treatment with trypsin or heat. The molecular size was determined to be about 82 kDa by ligand blotting. The active component was partially purified by column chromatography. It is suggested that this molecule interacts with the domain of NOF responsible for its neurite-promoting activity and may modulate NOF activity during development in vivo.