Fig. 2. C/EBP functional domains, protein interaction regions and phosphorylation sites. The two major translational isoforms, p42 and p30, are shown. Three distinct transactivation elements (TE-I, TE-II and TE-III) have been identified (Friedman and McKnight, 1990; Nerlov and Ziff, 1994). Sequences mediating binding to various effector proteins regulating cell-cycle arrest are indicated; brackets denote regions whose boundaries are only approximately known. Two different CDK interaction regions have been reported (see text). Functionally relevant phosphoacceptor sites are depicted in blue.