Substrate-bound GP130/F11 will promote neurite outgrowth: evidence for a cell surface receptor

GP130/F11 is a neuronal cell adhesion molecule belonging to the Ig superfamily. Preliminary evidence suggests that it may be important for the fasciculation of axons and cell-cell interactions during synaptogenesis. Previous work has shown that when F3 (the mouse homologue) is transfected into Chinese hamster ovary (CHO) cells it will act as a substrate for neuronal growth and adhesion. In this study we have shown that isolated GP130/F11 will also act as a substrate for the growth of chick dorsal root ganglia cell neurons. The concentration of GP130/F11 on the surface of sympathetic neurons, grown for one day in culture was approximately 40 ng cm-2 which was comparable to the levels required to stimulate neurite outgrowth. Deglycosylation of GP130/F11 or partial denaturation by boiling did not abolish the activity. However, after treatment with dithiothreitol, GP130/F11 was no longer capable of stimulating neurite outgrowth. GP130/F11 will also stimulate neurite outgrowth from forebrain neurons from 7 to 9-day-old embryos. These do not express GP130/F11 until around day 10, providing further evidence that GP130/F11 interacts with an as yet unknown cell surface receptor.