title: Expression of the Stp1 LMW-PTP and inhibition of protein CK2 display a cooperative effect on immunophilin Fpr3 tyrosine phosphorylation and Saccharomyces cerevisiae growth.
abstract: Although the yeast genome does not encode bona fide protein tyrosine kinases, tyrosine-phosphorylated proteins are numerous, suggesting that besides dual-specificity kinases, some Ser/Thr kinases are also committed to tyrosine phosphorylation in Saccharomyces cerevisiae. Here we show that blockage of the highly pleiotropic Ser/Thr kinase CK2 with a specific inhibitor synergizes with the overexpression of Stp1 low-molecular-weight protein tyrosine phosphatase (PTP) in inducing a severe growth-defective phenotype, consistent with a prominent role for CK2 in tyrosine phosphorylation in yeast. We also present in vivo evidence that immunophilin Fpr3, the only tyrosine-phosphorylated CK2 substrate recognized so far, interacts with and is dephosphorylated by Spt1. These data disclose a functional correlation between CK2 and LMW-PTPs, and suggest that reversible phosphorylation of Fpr3 plays a role in the regulation of growth rate and budding in S. cerevisiae.
authors.affiliation: Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Viale G. Morgagni 50, 50134 Firenze, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marchetta
authors.forename: T
authors.initials: T
authors.lastname: Gamberi
authors.forename: S
authors.initials: S
authors.lastname: Sarno
authors.forename: F
authors.initials: F
authors.lastname: Magherini
authors.forename: G
authors.initials: G
authors.lastname: Raugei
authors.forename: G
authors.initials: G
authors.lastname: Camici
authors.forename: L A
authors.initials: LA
authors.lastname: Pinna
authors.forename: A
authors.initials: A
authors.lastname: Modesti
mesh_terms: D047390:Casein Kinase II; D002453:Cell Cycle; D002455:Cell Division; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015151:Immunoblotting; D020104:Immunophilins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000502:physiology; D010641:Phenotype; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D016601:RNA-Binding Proteins / Q000096:biosynthesis* / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis* / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis* / Q000502:physiology; D014230:Triazoles / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism
chemical_list: C405354:4,5,6,7-tetrabromobenzotriazole; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; C074632:STP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014230:Triazoles; D014443:Tyrosine; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; C403327:FPR3 protein, S cerevisiae; D020104:Immunophilins