Saccharomyces cerevisiae protein phosphatase Ppz1 and protein kinases Sat4 and Hal5 are involved in the control of subcellular localization of Gln3 by likely regulating its phosphorylation state.
A Saccharomyces cerevisiae mutant lacking PPZ1, encoding a serine/threonine protein phosphatase (PPase), is caffeine-sensitive. To clarify the function of Ppz1 in resistance to caffeine, we attempted systematically to identify protein kinase (PKase) whose disruption lead to suppression of caffeine sensitive phenotype of the ∆ppz1 disruptant since disruption of PPZ1 might cause caffeine sensitivity by increasing its phosphorylated substrates and we presumed that disruption of genes for PKase sharing the substrate with Ppz1 could restore the resistance through bypassing necessity for dephosphorylation of substrates. Among the 102 viable pkase disruptions, disruption of either SAT4 or HAL5 suppressed the caffeine sensitivity phenotype and increased expression of ENA1, encoding a P-type ATPase of the ∆ppz1 disruptant. Because increased expression of ENA1 in the ∆ppz1 disruptant was found to be suppressed by disruption of GLN3, localization and phosphorylation of Gln3 in the ∆ppz1 disruptant was compared to that in the ∆ppz1∆sat4 and ∆ppz1∆hal5 double disruptants. Gln3 was found to accumulate in the nucleus in the ∆ppz1 disruptant, and this nuclear localization was abolished by disruption of either SAT4 or HAL5. Interestingly, the level of Gln3 phosphorylation in the ∆ppz1∆sat4 and ∆ppz1∆hal5 disruptants decreased relative to wild type independent of caffeine. From these observations, we conclude that Ppz1 controls Gln3 localization by regulating its phosphorylation state in combination with Sat4 and Hal5.
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Masataka
M
Hirasaki
Masaya
M
Horiguchi
Minori
M
Numamoto
Minetaka
M
Sugiyama
Yoshinobu
Y
Kaneko
Yasuhisa
Y
Nogi
Satoshi
S
Harashima
D002110:Caffeine / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C086375:ENA1 protein, S cerevisiae; C071664:GLN3 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D002110:Caffeine; D011494:Protein Kinases; C522341:Hal5 protein, S cerevisiae; C072246:SAT4 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C075119:PPZ1 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D000254:Sodium-Potassium-Exchanging ATPase