NEUROGRANIN, A B-50 GAP-43-IMMUNOREACTIVE C-KINASE SUBSTRATE (BICKS),IS ADP-RIBOSYLATED/

Neurogranin is a neurone-specific, B-50-immunoreactive C-kinase substr ate that has limited homology to, but considerable biochemical similar ity to B-50/GAP43. The most significant differences between these two proteins are their cellular localisation and molecular mass (Neurogran in, 7.5 kDA cytosolic; and B-50, 25 kDa membranal). An understanding o f the similarities and differences between Neurogranin and B-50 may fa cilitate the elucidation of their hitherto elusive functions in the ne rvous system. The results of the present study demonstrate that, in co mmon with B-50, Neurogranin is a, substrate for ADP-ribosyltransferase s. This finding is discussed with regard to the concept of molecular f lexibility of B-50-like proteins as the basis of their putatively dive rse roles in the nervous system.