Modulation of ATP-Dependent Chromatin-Remodeling Complexes by Inositol Polyphosphates

Eukaryotes use adenosine triphosphate (ATP)-dependent chromatin-remodeling complexes to regulate gene expression. Here, we show that inositol polyphosphates can modulate the activities of several chromatin-remodeling complexes in vitro. Inositol hexakisphosphate (IP₆) inhibits nucleosome mobilization by NURF, ISW2, and INO80 complexes. In contrast, nucleosome mobilization by the yeast SWI/SNF complex is stimulated by inositol tetrakisphosphate (IP₄) and inositol pentakisphosphate (IP₅). We demonstrate that mutations in genes encoding inositol polyphosphate kinases that produce IP₄, IP₅, and IP₆ impair transcription in vivo. These results provide a link between inositol polyphosphates, chromatin remodeling, and gene expression.