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http://purl.uniprot.org/citations/9154797http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/9154797http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/9154797http://www.w3.org/2000/01/rdf-schema#comment"Eukaryotic polyamine transport systems have not yet been characterized at the molecular level. We have used transposon mutagenesis to identify genes controlling polyamine transport in Saccharomyces cerevisiae. A haploid yeast strain was transformed with a genomic minitransposon- and lacZ-tagged library, and positive clones were selected for growth resistance to methylglyoxal bis(guanylhydrazone) (MGBG), a toxic polyamine analog. A 747-bp DNA fragment adjacent to the lacZ fusion gene rescued from one MGBG-resistant clone mapped to chromosome X within the coding region of a putative Ser/Thr protein kinase gene of previously unknown function (YJR059w, or STK2). A 304-amino-acid stretch comprising 11 of the 12 catalytic subdomains of Stk2p is approximately 83% homologous to the putative Pot1p/Kkt8p (Stk1p) protein kinase, a recently described activator of low-affinity spermine uptake in yeast. Saturable spermidine transport in stk2::lacZ mutants had an approximately fivefold-lower affinity and twofold-lower Vmax than in the parental strain. Transformation of stk2::lacZ cells with the STK2 gene cloned into a single-copy expression vector restored spermidine transport to wild-type levels. Single mutants lacking the catalytic kinase subdomains of STK1 exhibited normal parameters for the initial rate of spermidine transport but showed a time-dependent decrease in total polyamine accumulation and a low-level resistance to toxic polyamine analogs. Spermidine transport was repressed by prior incubation with exogenous spermidine. Exogenous polyamine deprivation also derepressed residual spermidine transport in stk2::lacZ mutants, but simultaneous disruption of STK1 and STK2 virtually abolished high-affinity spermidine transport under both repressed and derepressed conditions. On the other hand, putrescine uptake was also deficient in stk2::lacZ mutants but was not repressed by exogenous spermidine. Interestingly, stk2::lacZ mutants showed increased growth resistance to Li+ and Na+, suggesting a regulatory relationship between polyamine and monovalent inorganic cation transport. These results indicate that the putative STK2 Ser/Thr kinase gene is an essential determinant of high-affinity polyamine transport in yeast whereas its close homolog STK1 mostly affects a lower-affinity, low-capacity polyamine transport activity."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.org/dc/terms/identifier"doi:10.1128/mcb.17.6.2994"xsd:string
http://purl.uniprot.org/citations/9154797http://purl.org/dc/terms/identifier"doi:10.1128/mcb.17.6.2994"xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Poulin R."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Poulin R."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Verma S."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Verma S."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Ramotar D."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Ramotar D."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Kaouass M."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Kaouass M."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Gamache I."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Gamache I."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Audette M."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Audette M."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Torossian K."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"Torossian K."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"de Montigny D."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/author"de Montigny D."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/date"1997"xsd:gYear
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/date"1997"xsd:gYear
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/name"Mol. Cell. Biol."xsd:string
http://purl.uniprot.org/citations/9154797http://purl.uniprot.org/core/name"Mol. Cell. Biol."xsd:string
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