RAT P67 GBP IS INDUCED BY INTERFERON-GAMMA AND ISOPRENOID-MODIFIED INMACROPHAGES

The guanylate binding proteins, GBPs, are a family of interferon-induc ed GTP-binding proteins that include the rat p67. We report here that rat p67, for which interferon regulation had nor previously been demon strated, is induced by IFN-gamma and also by LPS in both cultured bone marrow-derived macrophages and microglia. The basal level of rat p67 in macrophages is low but increases dramatically between 2 and 4 hours after treating cells with either IFN-gamma or LPS. It then remains el evated over the next 24 hours. Rat p67 is isoprenoid modified. The iso prenoid modification was detected in p67 isolated both from primary IF N-gamma-activated macrophages and when the gene for p67 was transfecte d into COS cells. This is the first demonstration of in vivo prenylati on of a GBP. The interferon regulation and prenylation of rat p67 poin t toward this protein being significant in the functions of both activ ated macrophages and microglia. (C) 1996 Academic Press, Inc.