Interferon gamma induces the myristoylation of a 48-kDa protein in macrophages.

The lymphokine interferon gamma (IFN-gamma) induces the selective myristoylation of a macrophage protein with an apparent molecular mass of 48 kDa. The myristic acid-protein bond is resistant to treatment with hydroxylamine, suggesting that the fatty acid moiety is in an amide linkage. As little as 1 unit of IFN-gamma per ml induces the myristoylation of the 48-kDa protein, with half-maximal myristoylation being observed with 4 units/ml. The effect is observed within 1 hr after exposure to IFN-gamma and is maximal by 3-4 hr, after which it declines. IFN-alpha does not induce the myristoylation of the 48-kDa protein, and IFN-beta does so very poorly. Neither IFN-alpha nor IFN-beta has any effect on IFN-gamma-induced myristoylation of the 48-kDa protein. The 48-kDa protein is constitutively myristoylated in murine macrophages that have been activated in vivo by intraperitoneal injection of Corynebacterium parvum, suggesting that it may be an early intermediate in the activation of macrophages.