Inositol polyphosphate multikinase (ArgRIII) determines nuclear mRNA export in Saccharomyces cerevisiae.
The ARGRIII gene of Saccharomyces cerevisiae encodes a transcriptional regulator that also has inositol polyphosphate multikinase (ipmk) activity [Saiardi et al. (1999) Curr. Biol. 9, 1323-1326]. To investigate how inositol phosphates regulate gene expression, we disrupted the ARGRIII gene. This mutation impaired nuclear mRNA export, slowed cell growth, increased cellular [InsP(3)] 170-fold and decreased [InsP(6)] 100-fold, indicating reduced phosphorylation of InsP(3) to InsP(6). Levels of diphosphoinositol polyphosphates were decreased much less dramatically than was InsP(6). Low levels of InsP(6), and considerable quantities of Ins(1,3,4,5)P(4), were synthesized by an ipmk-independent route. Transcriptional control by ipmk reflects that it is a pivotal regulator of nuclear mRNA export via inositol phosphate metabolism.
Saiardi
A
A
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Caffrey
J J
JJ
Snyder
S H
SH
Shears
S B
SB
D001692:Biological Transport / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005656:Fungal Proteins / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor); D010833:Phytic Acid / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000235:genetics
D005656:Fungal Proteins; D007295:Inositol Phosphates; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D010833:Phytic Acid; D015544:Inositol 1,4,5-Trisphosphate; C425775:ARG82 protein, S cerevisiae; D017853:Phosphotransferases (Alcohol Group Acceptor)