Yeast reveals unexpected roles and regulatory features of aquaporins and aquaglyceroporins

Ahmadpour, Doryaneh; Geijer, Cecilia; Tamás, Markus J.; Lindkvist‐Petersson, Karin; Hohmann, Stefan

doi:10.1016/j.bbagen.2013.09.027

Cited by 59 publications

(31 citation statements)

References 90 publications

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“…In bacteria, it has been postulated that glycerol modulates water permeation in the micromolar range, whereas at millimolar concentrations, E. coli GlpF is glycerol saturated, occluding the conducting pore (Chen, 2013). In yeast, S. cerevisiae Fps1 plays critical roles in osmoregulation by modulating the accumulation of glycerol (reviewed in Ahmadpour et al, 2014). Here, we showed that under mild osmotic stress, double knockdowns displayed shorter pollen tubes, suggesting a role for NIP4s in osmoregulation.…”

Section: Nip4;1 and Nip4;2 Transport Water And Glycerol In Oocytesmentioning

confidence: 60%

Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana

et al. 2016

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Section: Nip4;1 and Nip4;2 Transport Water And Glycerol In Oocytesmentioning

confidence: 60%

Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana

et al. 2016

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“…As a result, the glycolytic flux is directed mainly toward glycerol formation to the detriment of biomass production (Hohmann and Mager, 2007;PetelenzKurdziel et al, 2013). Furthermore, the HOG pathway also contributes to activate various mechanisms that serve to retain intracellular glycerol, as the activation of glycerol carriers coded by gene STL1 and the closure of the aquaglyceroporin channel Fps1 to prevent the loss of glycerol (see reviews of Hohmann, 2009 andAhmadpour et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Short-term response of different Saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in grape must: RT-qPCR study and metabolite analysis

et al. 2015

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a b s t r a c tDuring the winemaking process, glycerol synthesis represents the first adaption response of Saccharomyces cerevisiae to osmotic stress after inoculation in grape must. We have implemented an RT-qPCR (Reverse Transcription-quantitative PCR) methodology with a preventive evaluation of candidate reference genes, to study six target genes related to glycerol synthesis (GPD1, GPD2, GPP2 and GPP1) and flux (STL1 and FPS1), and three ALD genes coding for aldehyde dehydrogenase involved in redox equilibrium via acetate production. The mRNA level in three strains, characterized by different metabolite production, was monitored in the first 120 min from inoculation into natural grape must. Expression analysis shows a transient response of genes GPD1, GPD2, GPP2, GPP1 and STL1 with differences among strains in term of mRNA abundance, while FPS1 was expressed constitutively. The transient response and different expression intensity among strains, in relation to the intracellular glycerol accumulation pattern, prove the negative feedback control via the HOG (High Osmolarity Glycerol) signalling pathway in S. cerevisiae wine strains under winery conditions. Among the ALD genes, only ALD6 was moderately induced in the hyperosmotic environment but not in all strains tested, while ALD3 and ALD4 were drastically glucose repressed. The intensity of transcription of ALD6 and ALD3 seems to be related to different acetate production found among the strains.

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“…Regulation of Fps1 in response to changes in osmolarity involves the mitogen-activated protein kinase (MAPK) Hog1 (highosmolarity glycerol response) (4,21,22), a homolog of the mammalian p38 MAPK, which binds to the N-terminal cytoplasmic domain of Fps1 (23). Hog1 activated in response to hyperosmotic stress is recruited to a docking site within the Fps1 N-terminal domain, which it uses as a platform from which to phosphorylate Rgc2 (and Rgc1), thereby causing its eviction from the Fps1 C-terminal domain and consequent closure of the channel (18).…”

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confidence: 99%

Rgc2 Regulator of Glycerol Channel Fps1 Functions as a Homo- and Heterodimer with Rgc1

Lee

Levin

2015

Eukaryot Cell

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The plasma membrane aquaglyceroporin Fps1 is responsible for glycerol transport in yeast in response to changes in extracellular osmolarity. Fps1 functions as a homotetramer, and control of its channel activity in response to hyperosmotic shock involves a redundant pair of fungus-specific regulators, Rgc1 and Rgc2 (regulators of the glycerol channel), and the mitogen-activatd protein kinase (MAPK) Hog1 (high-osmolarity glycerol response). Rgc1 and Rgc2 maintain Fps1 in an open-channel state by binding to its C-terminal cytoplasmic domain. Phosphorylation of Rgc1 and Rgc2 by Hog1 induces their eviction from Fps1 and consequent channel closure. In the absence of Fps1 channel function, cells experience chronic cell wall stress, which may be exploited for antifungal drug development. We show here that Rgc1 and Rgc2 form homodimers and heterodimers with each other and that dimer formation of Rgc2 is mediated by its N-terminal domain. Mutations that prevent Rgc2 dimerization block its ability to open Fps1. Therefore, the Rgc-Rgc dimer interface might be an attractive drug target. Under conditions of high-osmolarity stress, many fungal species, including Saccharomyces cerevisiae, maintain osmotic equilibrium by producing and retaining high concentrations of glycerol as a compatible solute (1). Intracellular glycerol concentration is regulated in S. cerevisiae in part by the Fps1 plasma membrane glycerol channel (2-4). Increased external osmolarity induces Fps1 closure, whereas decreased osmolarity causes channel opening, both within seconds of the change in external osmolarity (4). This channel is required for survival of a hypo-osmotic shock, when yeast cells must export glycerol rapidly to prevent bursting (2, 4). Fps1 is also required for controlling turgor pressure during fusion of mating yeast cells (5).Fps1 is a member of the major intrinsic protein (MIP) family of channel proteins. The MIP family is subdivided into members that are selectively permeable to water (aquaporins) and those permeated by glycerol and to a lesser extent by water, called aquaglyceroporins, or glycerol facilitators (6, 7). Numerous aquaporins have been shown to function as homotetramers, with each monomer possessing its own channel (8-13). Fps1 similarly functions as a homotetramer (14).Relative to nonfungal aquaglyceroporins, Fps1 possesses Nterminal and C-terminal cytoplasmic extensions that are important for its regulation (15, 16). Fps1 activity is controlled by a pair of redundant positive regulators, named Rgc1 and Rgc2 (for regulator of the glycerol channel; encoded by YPR115W and YGR097W, respectively) (17), which maintain Fps1 in an openchannel conformation through binding to its C-terminal cytoplasmic domain (18). Aside from centrally located pleckstrin homology (PH) domains, which are critical for their interaction with Fps1, Rgc1 and Rgc2 do not possess any other identifiable domains. The RGC2 gene was suggested previously to play a role in cell wall biogenesis through its identification in a genetic screen for activators of t...

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Yeast reveals unexpected roles and regulatory features of aquaporins and aquaglyceroporins

Cited by 59 publications

References 90 publications

Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana

Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana

Short-term response of different Saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in grape must: RT-qPCR study and metabolite analysis

Rgc2 Regulator of Glycerol Channel Fps1 Functions as a Homo- and Heterodimer with Rgc1

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