Transcriptional regulation: a new dominion for inositol phosphate signaling?

The diverse phosphorylation patterns of the six-carbon inositol ring generates a mesmerizing wealth of inositol phosphates but we have little insight into the precise cellular roles of most members of this family. Therefore, new information on these roles is very welcome. The discovery by two independent groups(1, 2) that the Arg82 transcriptional regulator from Saccharomyces cerevisiae has inositol phosphate kinase activity is intriguing in this respect. One group proposes that these events directly affect the function of a specific, multimeric transcriptional complex.(2) It will be argued here, however, that available data do not entirely support such a direct role for Arg82 in transcription. The potential relevance of these findings to higher organisms will also be discussed.