TURNOVER STUDIES OF THE NEURAL CELL-ADHESION MOLECULE NCAM - DEGRADATION OF NCAM IN PC12 CELLS DEPENDS ON THE PRESENCE OF NGF

The neural cell adhesion molecule NCAM is a member of the immunoglobul in superfamily and involved in path finding and outgrowth of neurites in vitro. PC12 cells express two major isoforms of NCAM (NCAM180 and N CAM140) and undergo neuronal differentiation, e.g., neurite formation, in response to NGF. Using this cell system, we determined the half-ti me time of both NCAM isoforms in the absence and presence of NGF. Half -life time of NCAM140 is similar in the presence and absence of NGF, w hereas the half-life Dime of NCAM180 is increased in the presence of N GF. Furthermore, we quantified protein expression of both NCAM isoform s in the presence or absence of NGF and found a decrease of NCAM prote in expression in course of neuronal differentiation. (C) 1997 Academic Press.