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The transcriptional regulator, Arg82, is a hybrid kinase with both monophosphoinositol and diphosphoinositol polyphosphate synthase activity
Author(s) -
Zhang Tong,
Caffrey James J,
Shears Stephen B
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02351-1
Subject(s) - inositol , polyphosphate , regulator , biochemistry , kinase , saccharomyces cerevisiae , phosphorylation , biology , yeast , inositol phosphate , transcriptional regulation , glycosyltransferase , second messenger system , enzyme , gene , microbiology and biotechnology , gene expression , phosphate , receptor
The Arg82 gene of Saccharomyces cerevisiae encodes a transcriptional regulator that phosphorylates inositol 1,4,5‐trisphosphate [Saiardi et al. (1999) Curr. Biol. 9, 1323–1326]. However, some controversy has surrounded the nature of the reaction products. We now show that Arg82 phosphorylates inositol 1,3,4,5‐tetrakisphosphate to inositol pentakisphosphate, which is itself converted to two isomers of diphosphoinositol tetrakisphosphate, one of which has never previously been identified. One of the diphosphoinositol phosphates was further phosphorylated by a yeast cell lysate. We propose that Arg82 is an ancestral precursor of two distinct and specific enzyme families: inositol 1,4,5‐trisphosphate kinases and diphosphoinositol polyphosphate synthases.