Pheromone-induced signal transduction in Saccharomyces cerevisiae requires the sequential function of three protein kinases.

Zhou, Zhaoqing; Gartner, Anton; Cade, Rebecca; Ammerer, Gustav; Errede, Beverly

doi:10.1128/mcb.13.4.2069

Cited by 135 publications

(113 citation statements)

References 51 publications

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“…Upon exposure to pheromone, Ste7 is activated by phosphorylation by Ste11 and becomes hyperphosphorylated in the presence of Fus3/Kss1 (Zhou et al, 1993;Neiman and Herskowitz, 1994). As shown in Figure 4B, the degree of hyperphosphorylation of Ste7 as well as Ste7 protein levels is strongly reduced in mutant strains.…”

Section: Basal and Induced Phosphorylation Of Ste7 Is Reducedmentioning

confidence: 76%

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Hsp90 Is Required for Pheromone Signaling in Yeast

Louvion

Abbas-Terki

Picard

1998

MBoC

107

129

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The heat-shock protein 90 (Hsp90) is a cytosolic molecular chaperone that is highly abundant even at normal temperature. Specific functions for Hsp90 have been proposed based on the characterization of its interactions with certain transcription factors and kinases including Raf in vertebrates and flies. We therefore decided to address the role of Hsp90 for MAP kinase pathways in the budding yeast, an organism amenable to both genetic and biochemical analyses. We found that both basal and induced activities of the pheromone-signaling pathway depend on Hsp90. Signaling is defective in strains expressing low levels or point mutants of yeast Hsp90 (Hsp82), or human Hsp90␤ instead of the wild-type protein. Ste11, a yeast equivalent of Raf, forms complexes with wild-type Hsp90 and depends on Hsp90 function for accumulation. For budding yeast, Ste11 represents the first identified endogenous "substrate" of Hsp90. Moreover, Hsp90 functions in steroid receptor and pheromone signaling can be genetically separated as the Hsp82 point mutant T525I and the human Hsp90␤ are specifically defective for the former and the latter, respectively. These findings further corroborate the view that molecular chaperones must also be considered as transient or stable components of signal transduction pathways. INTRODUCTIONThe 90-kDa heat-shock protein (Hsp90) 1 (for reviews, see Jakob and Buchner, 1994;Csermely et al., 1998) is an ubiquitous and abundantly expressed cytosolic protein even at normal temperature. It is highly conserved from bacteria to mammals. Two genes encode closely related isoforms in mammals as well as in the budding yeast Saccharomyces cerevisiae. Deletion experiments in yeast have shown that the expression of at least one of the two Hsp90 isoforms, either Hsp82 or Hsc82, is essential for viability (Borkovich et al., 1989). Similarly, many mutant alleles of the Drosophila HSP90 homolog, HSP83, are embryonic lethals over a deficiency of the locus (van der Straten et al., 1997), whereas the Escherichia coli homolog of Hsp90, HtpG, appears to be dispensable (Bardwell and Craig, 1988). Hsp90 can act as a molecular chaperone in vitro to promote refolding of denatured proteins (Wiech et al., 1992;Yonehara et al., 1996; see also Shaknovich et al., 1992;Shue and Kohtz, 1994), to hold denatured proteins in a folding-competent state for other chaperones (Freeman and Morimoto, 1996;Yonehara et al., 1996) and to prevent protein unfolding and aggregation (Miyata and Yahara, 1992;Jakob et al., 1995aJakob et al., , 1995bYonehara et al., 1996).The interaction of Hsp90 with steroid receptors, which can be thought of as a signal transduction complex, has been the most extensively investigated. A variety of in vitro and in vivo studies have revealed that steroid receptors are complexed with Hsp90 and several other proteins in the absence of hormone (for review, see Pratt and Toft, 1997). Upon ligand binding, the hormone binding domain (HBD) undergoes a conformational change that results in the release of Hsp90 and the concomitant acti...

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Section: Basal and Induced Phosphorylation Of Ste7 Is Reducedmentioning

confidence: 76%

“…It contains the CYC1 promoter and Ste7-coding sequences from plasmid pNC318 (Zhou et al, 1993) excised as a SalI-HindIII fragment and cloned into the SalI-SmaI linearized plasmid pRS316 (Sikorski and Hieter, 1989).…”

Section: Molecular Biology Of the Cell 3072mentioning

confidence: 99%

Hsp90 Is Required for Pheromone Signaling in Yeast

Louvion

Abbas-Terki

Picard

1998

MBoC

107

129

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“…To allow measurement of Fus3 kinase activity by immune complex assays, the DOA4 and doa4C 571 S strains expressed a myc epitope-tagged version of Fus3 (Fus3M) from the constitutive TPI1 promoter (6). Protein extracts were prepared from samples before pheromone addition (t ϭ 0) and at the indicated times during pheromone induction.…”

Section: Ste11 Protein Stability Is Not Affected By Hyperosmotic Stressmentioning

confidence: 99%

“…C699-75 (bar1⌬::HisG FUS1-lacZ::LEU2 fus3⌬::ADE2, kss1⌬::URA3) was derived from strain C699-15 by replacement of the FUS3 locus with a BamHI-SalI fragment from pSL2223 carrying the fus3⌬::ADE2 allele and the KSS1 locus using an EcoRI-SphI fragment from pBC65 carrying the kss1⌬::URA3 allele (20,26). Strain E929-6C (MATa cyc1 CYC7-H2 can1leu2-3, 112 trp1⌬ 1 ura3-52) and strain FP50 (MATa ssk2⌬::LEU2 ssk22⌬::LEU2 ste11::HIS3 ura3 leu2 his3), which retains the function of only the Sho1-and Ste11-dependent branch of the osmotic response pathway, have been described (6,16). This paper was submitted directly (Track II) to the PNAS office.…”

Section: Methodsmentioning

confidence: 99%

“…The prototype MAPK kinase kinase (MEKK) is the yeast enzyme Ste11, which was identified for its role in pheromone-induced mating differentiation (1,2). In the mating MAPK cascade, Ste11 phosphorylates and activates the MAPK kinase (MEK), Ste7, which in turn phosphorylates and activates two MAPKs, Fus3 and Kss1 (3)(4)(5)(6)(7). Although Fus3 and Kss1 kinase activity is induced to an equivalent extent in pheromonetreated cells, Fus3, but not Kss1, has specificity for critical substrates that are dedicated to the mating differentiation response (7).…”

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confidence: 99%

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Pheromone induction promotes Ste11 degradation through a MAPK feedback and ubiquitin-dependent mechanism

Esch

Errede

2002

Proc. Natl. Acad. Sci. U.S.A.

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Ste11 is the mitogen-activated protein kinase (MAPK) kinase kinase in the MAPK cascades that mediate mating, high osmolarity glycerol, and filamentous growth responses in Saccharomyces cerevisiae. We show stimulation of the mating pathway by pheromone promotes an accelerated turnover of Ste11 through a MAPK feedback and ubiquitin-dependent mechanism. This degradation is pathway specific, because Ste11 is stable during activation of the high osmolarity glycerol pathway. Because the steady-state amount of Ste11 does not change significantly during pheromone induction, we infer that maintenance of MAPK activation involves repeated cycles in which naïve Ste11 is activated and then targeted for degradation. This model predicts that elimination of active Ste11 would rapidly curtail MAPK activation upon attenuation of the upstream signal. This prediction is confirmed by the finding that blocking ubiquitin-dependent Ste11 degradation during pheromone induction abolishes the characteristic attenuation profile for MAPK activation.

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Scaffold proteins in MAP kinase signaling: more than simple passive activating platforms

Dard

Peter

2006

Bioessays

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Due to the central position of scaffold proteins in numerous signaling networks, especially in MAPK pathways, considerable efforts have been made to identify new scaffolds and to characterize their function and regulation. Most of our knowledge stems from studies of yeast MAPK scaffolds, but the identification of such scaffolds in higher eukaryotes provided a new dimension to this field and led to exciting and promising new insights into the regulation of MAPK signaling. In this review, we shortly summarize the well-established basic functions of scaffolds in yeast and highlight concepts emerging from recent studies in yeast and higher eukaryotes. In particular, we discuss how scaffolds may actively influence MAPK signaling by inducing conformational changes of bound kinases or substrates, by controlling the localization of activated MAPK and the extent and output of MAPK activation, and by modulating MAPK kinetics through the recruitment of phosphatases or ubiquitin-ligases. Finally, we summarize the current knowledge of scaffold regulation, and how these events may be functionally important for MAPK signaling.

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Pheromone-induced signal transduction in Saccharomyces cerevisiae requires the sequential function of three protein kinases.

Abstract: MATERIALS AND METHODS Plasmid constructions. We expressed STE7 from the CYCI promoter for its overproduction in S.

Cited by 135 publications

References 51 publications

Hsp90 Is Required for Pheromone Signaling in Yeast

Hsp90 Is Required for Pheromone Signaling in Yeast

Pheromone induction promotes Ste11 degradation through a MAPK feedback and ubiquitin-dependent mechanism

Scaffold proteins in MAP kinase signaling: more than simple passive activating platforms

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