The pheromone response pathway of<i>Kluyveromyces lactis</i>

Coria, Roberto; Kawasaki, Laura; Torres-Quiroz, Francisco; Ongay‐Larios, Laura; Sánchez-Paredes, Edith; Velázquez-Zavala, Nancy; Navarro-Olmos, Rocío; Rodríguez-González, Miriam; Aguilar-Corachán, Rodrigo; Coello, Gerardo

doi:10.1111/j.1567-1364.2005.00022.x

Cited by 15 publications

(13 citation statements)

References 66 publications

(78 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In previous work, we have demonstrated that both the G␣ (KlGpa1p) and G␤ (KlSte4p) subunits of the heterotrimeric G protein trigger the mating pheromone response pathway in K. lactis (6,14,31). Additionally, we have found that this activation requires the transcription factor KlSte12p (14,19).…”

Section: Resultsmentioning

confidence: 99%

Protein Kinases Involved in Mating and Osmotic Stress in the Yeast Kluyveromyces lactis

Kawasaki¹,

Castañeda‐Bueno²,

Sánchez-Paredes³

et al. 2008

Eukaryot Cell

Self Cite

View full text Add to dashboard Cite

Systematic disruption of genes encoding kinases and mitogen-activated protein kinases (MAPKs) was performed in Kluyveromyces lactis haploid cells. The mutated strains were assayed by their capacity to mate and to respond to hyperosmotic stress. The K. lactis Ste11p (KlSte11p) MAPK kinase kinase (MAPKKK) was found to act in both mating and osmoresponse pathways while the scaffold KlSte5p and the MAPK KlFus3p appeared to be specific for mating. The p21-activated kinase KlSte20p and the kinase KlSte50p participated in both pathways. Protein association experiments showed interaction of KlSte50p and KlSte20p with G␣ and G␤, respectively, the G protein subunits involved in the mating pathway. Both KlSte50p and KlSte20p also showed interaction with KlSte11p. Disruption mutants of the K. lactis PBS2 (KlPBS2) and KlHOG1 genes of the canonical osmotic response pathway resulted in mutations sensitive to high salt and high sorbitol but dispensable for mating. Mutations that eliminate the MAPKK KlSte7p activity had a strong effect on mating and also showed sensitivity to osmotic stress. Finally, we found evidence of physical interaction between KlSte7p and KlHog1p, in addition to diminished Hog1p phosphorylation after a hyperosmotic shock in cells lacking KlSte7p. This study reveals novel roles for components of transduction systems in yeast.

show abstract

Section: Resultsmentioning

confidence: 99%

Protein Kinases Involved in Mating and Osmotic Stress in the Yeast Kluyveromyces lactis

Kawasaki¹,

Castañeda‐Bueno²,

Sánchez-Paredes³

et al. 2008

Eukaryot Cell

Self Cite

View full text Add to dashboard Cite

show abstract

“…E, N and I. Aromatic residues located in TM5 (F204) and in TM6 (Y266) have been postulated as interaction points of the ScSte2p receptor with aromatic residues (W1 and W3) of the α-pheromone (Lin et al, 2003;Naider and Becker, 2004). Aromatic residues are also present in these positions in the KlSte2p receptor (Y in both positions) and may have a role in making contact with putative W residues of the K. lactis sexual pheromone (Coria et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

The KlSTE2 and KlSTE3 genes encode MATα‐ and MATa‐specific G‐protein‐coupled receptors, respectively, which are required for mating of Kluyveromyces lactis haploid cells

Torres-Quiroz

Kawasaki

Rodríguez-González

et al. 2006

Yeast

Self Cite

View full text Add to dashboard Cite

Mating in yeast is initiated by binding of pheromone to G-protein-coupled receptors expressed in haploid cells. We analysed the role of KlSte2p and KlSte3p receptors in the Kluyveromyces lactis mating pathway. By sequence analysis, KlSte2p and KlSte3p are the homologues of the Saccharomyces cerevisiae α-pheromone and a-pheromone receptors, respectively. However, by expression experiments, we determined that KlSTE2 gene is expressed in the cells typified as MAT α and therefore is the receptor for the K. lactis a-pheromone and KlSTE3 gene is expressed in the MAT a cells and binds the α-pheromone. The KlSTE2 gene is silent in MAT a cells, while it is highly expressed in MATα cells, and conversely the KlSTE3 gene is expressed in MAT a cells and repressed in MATα cells. Disruption mutants of both genes were found to be sterile, and this defect is reversed by plasmidic copies of each gene. The cytoplasmic C-terminus of KlSte3p interacts strongly with the KlGpa1p (Gα) subunit, which is involved in the transduction of the pheromone stimulus to induce mating. Remarkably, this same domain does not interact with a constitutive active allele of the Gα subunit, indicating that the C-terminus is able to discriminate between the active (GTP-bound) and inactive (GDP-bound) forms of the Gα subunit.

show abstract

“…In this organism, which like S. cerevisiae has an Ste5p homolog required for pheromone response (30), the absence of G␣ dramatically reduces, but does not eliminate, mating while the G␤ mutant is totally sterile (31). Surprisingly, however, the deletion of the putative ␥ subunit has been reported previously not to compromise mating (15); this distinction between the ␤ and ␥ subunit deletion phenotypes is inconsistent with the generic G-protein model and will require confirmation, but it could be explained if the G␤ subunit has an independent membranetargeting capacity.…”

Section: Fig 3 No Genes Inmentioning

confidence: 90%

“…This fungus has two ␣ subunits and a single copy each of ␤ and ␥ subunit-encoding genes. The Gpa1p subunit is implicated in mating (53), while Gpa2p is involved in cAMP regulation (15). In this organism, which like S. cerevisiae has an Ste5p homolog required for pheromone response (30), the absence of G␣ dramatically reduces, but does not eliminate, mating while the G␤ mutant is totally sterile (31).…”

Section: Fig 3 No Genes Inmentioning

confidence: 99%

Heterotrimeric G-Protein Subunit Function in Candida albicans : both the α and β Subunits of the Pheromone Response G Protein Are Required for Mating

2008

View full text Add to dashboard Cite

A pheromone-mediated signaling pathway that couples seven-transmembrane-domain (7-TMD) receptors to a mitogen-activated protein kinase module controls Candida albicans mating. 7-TMD receptors are typically connected to heterotrimeric G proteins whose activation regulates downstream effectors. Two G␣ subunits in C. albicans have been identified previously, both of which have been implicated in aspects of pheromone response. Cag1p was found to complement the mating pathway function of the pheromone receptor-coupled G␣ subunit in Saccharomyces cerevisiae, and Gpa2p was shown to have a role in the regulation of cyclic AMP signaling in C. albicans and to repress pheromone-mediated arrest. Here, we show that the disruption of CAG1 prevented mating, inactivated pheromone-mediated arrest and morphological changes, and blocked pheromone-mediated gene expression changes in opaque cells of C. albicans and that the overproduction of CAG1 suppressed the hyperactive cell cycle arrest exhibited by sst2 mutant cells. Because the disruption of the STE4 homolog constituting the only C. albicans gene for a heterotrimeric G␤ subunit also blocked mating and pheromone response, it appears that in this fungal pathogen the G␣ and G␤ subunits do not act antagonistically but, instead, are both required for the transmission of the mating signal.Many fungi have well-defined mating systems. Currently, the most thoroughly studied is that of the baker's or brewer's yeast Saccharomyces cerevisiae (2,12). In this yeast, a signaling pathway has been elucidated that contains cell type-specific receptors of the seven-transmembrane-domain class that are activated by cell type-specific pheromones (7, 46). The pheromone-bound receptor in turn activates a heterotrimeric G protein (17,43,61). In contrast to many of the related G-protein-linked receptor signaling pathways identified in mammalian systems that use the activated ␣ subunit to transfer the signal to the next step in the signaling cascade, the yeast pathway uses the ␤␥ subunit as the positive activator of downstream functions (61). The role of the free ␤␥ subunit is to bind the Ste5p scaffold protein (63) and the Ste20p p21-activated kinase (35) and trigger localization to the plasma membrane (50), as well as to direct polarized growth by binding the Far1p scaffold (8). The association of the Ste5p scaffold with the membrane (20, 21) ultimately turns on a mitogen-activated protein (MAP) kinase cascade, and the targets of the MAP kinase include critical elements in the mating response (14,22,33,58).In the yeast pathway, the G␣ subunit serves a role primarily in downregulating the signaling pathway. In its GDP-bound state, it associates with and inactivates the signaling ␤␥ subunit; the absence of Gpa1p leads to constitutive signaling and cell cycle arrest (17, 43) and, thus, to haploid-specific lethality (6). This genetic behavior is consistent with the predicted biochemical G-protein cycle; in the off state, the subunits are associated and inactive, while when activated, ␣ and ␤␥ have a relax...

show abstract

The pheromone response pathway ofKluyveromyces lactis

Cited by 15 publications

References 66 publications

Protein Kinases Involved in Mating and Osmotic Stress in the Yeast Kluyveromyces lactis

Protein Kinases Involved in Mating and Osmotic Stress in the Yeast Kluyveromyces lactis

The KlSTE2 and KlSTE3 genes encode MATα‐ and MATa‐specific G‐protein‐coupled receptors, respectively, which are required for mating of Kluyveromyces lactis haploid cells

Heterotrimeric G-Protein Subunit Function in Candida albicans : both the α and β Subunits of the Pheromone Response G Protein Are Required for Mating

Contact Info

Product

Resources

About