ENDOGENOUS ADP-RIBOSYLATION OF A G(ALPHA-I) PROTEIN IN BOVINE CILIARYBODY IS STIMULATED BY NITRIC-OXIDE

Five ciliary body membrane proteins were labeled when incubated with ( adenylate-P-32)NAD. Nitric oxide donors stimulated the labeling of 64, 40, and 29-30 kDa proteins and inhibited that of 58 and 56 kDa protei ns, The greatest influence of nitric oxide was on the 40 kDa protein: a 17-fold stimulation. Western blotting and immunoprecipitation with s pecific antibodies identified this protein as the alpha-subunit of G(i -1). Studies with inhibitors showed that the protein was mono-ADP-ribo sylated. Treatment of (P-32)NAD-labeled G(i-1) with Hg and analysis of the released radioactive material showed that the protein was ADP-rib osylated on a cysteine residue. (C) 1997 Academic Press.