Potassium and sodium uptake systems in fungi. The transporter diversity of Magnaporthe oryzae

Benito, Begoña; Garciadeblás, Blanca; Fraile-Escanciano, Ana; Rodríguez‐Navarro, Alonso

doi:10.1016/j.fgb.2011.03.002

Cited by 49 publications

(34 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both of the TRK and HAK families of transporter genes are distributed widely in the plant and fungal kingdoms (61)(62)(63)(64), and they can be complemented by two families of cation-pumping ATPases (10,11), although the latter are not present in Neurospora (65). In higher plants, regulation of K ϩ uptake involves not only several isoforms of the HAK and/or TRK proteins but also many specialized tissues and organs.…”

Section: Discussionmentioning

confidence: 99%

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

et al. 2013

View full text Add to dashboard Cite

b Fungi, plants, and bacteria accumulate potassium via two distinct molecular machines not directly coupled to ATP hydrolysis. The first, designated TRK, HKT, or KTR, has eight transmembrane helices and is folded like known potassium channels, while the second, designated HAK, KT, or KUP, has 12 transmembrane helices and resembles MFS class proteins. One of each type functions in the model organism Neurospora crassa, where both are readily accessible for biochemical, genetic, and electrophysiological characterization. We have now determined the operating balance between Trk1p and Hak1p under several important conditions, including potassium limitation and carbon starvation. Growth measurements, epitope tagging, and quantitative Western blotting have shown the gene HAK1 to be much more highly regulated than is TRK1. This conclusion follows from three experimental results: (i) Trk1p is expressed constitutively but at low levels, and it is barely sensitive to extracellular [K ؉ ] and/or the coexpression of HAK1; (ii) Hak1p is abundant but is markedly depressed by elevated extracellular concentrations of K ؉ and by coexpression of TRK1; and (iii) Carbon starvation slowly enhances Hak1p expression and depresses Trk1p expression, yielding steady-state Hak1p:Trk1p ratios of ϳ500:1, viz., 10-to 50-fold larger than that in K ؉ -and carbon-replete cells. Additionally, it appears that both potassium transporters can adjust kinetically to sustained low-K ؉ stress by means of progressively increasing transporter affinity for extracellular K ؉ . The underlying observations are (iv) that K ؉ influx via Trk1p remains nearly constant at ϳ9 mM/h when extracellular K ؉ is progressively depleted below 0.05 mM and (v) that K ؉ influx via Hak1p remains at ϳ3 mM/h when extracellular K ؉ is depleted below 0.1 mM.

show abstract

Section: Discussionmentioning

confidence: 99%

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Both are also involved in maintaining the pH homeostasis and are functionally interconnected [43]. Additional K + influx systems, like K + - H + symporter (Hak), K + -Na + P-type ATPase (Acu), and K + efflux channel Tok, were identified in the nonconventional yeasts (reviewed in [59], [60]), and were later shown to be widely present in several fungal species [61]. Importantly, fungi and plants show many similarities in the way in which the plasma membrane is energised, and K + and Na + are transported [36], [62], but the Na + -ATPases commonly present in fungi are absent in higher plants [63], [64].…”

Section: Introductionmentioning

confidence: 99%

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

et al. 2013

View full text Add to dashboard Cite

Hortaea werneckii, ascomycetous yeast from the order Capnodiales, shows an exceptional adaptability to osmotically stressful conditions. To investigate this unusual phenotype we obtained a draft genomic sequence of a H. werneckii strain isolated from hypersaline water of solar saltern. Two of its most striking characteristics that may be associated with a halotolerant lifestyle are the large genetic redundancy and the expansion of genes encoding metal cation transporters. Although no sexual state of H. werneckii has yet been described, a mating locus with characteristics of heterothallic fungi was found. The total assembly size of the genome is 51.6 Mb, larger than most phylogenetically related fungi, coding for almost twice the usual number of predicted genes (23333). The genome appears to have experienced a relatively recent whole genome duplication, and contains two highly identical gene copies of almost every protein. This is consistent with some previous studies that reported increases in genomic DNA content triggered by exposure to salt stress. In hypersaline conditions transmembrane ion transport is of utmost importance. The analysis of predicted metal cation transporters showed that most types of transporters experienced several gene duplications at various points during their evolution. Consequently they are present in much higher numbers than expected. The resulting diversity of transporters presents interesting biotechnological opportunities for improvement of halotolerance of salt-sensitive species. The involvement of plasma P-type H+ ATPases in adaptation to different concentrations of salt was indicated by their salt dependent transcription. This was not the case with vacuolar H+ ATPases, which were transcribed constitutively. The availability of this genomic sequence is expected to promote the research of H. werneckii. Studying its extreme halotolerance will not only contribute to our understanding of life in hypersaline environments, but should also identify targets for improving the salt- and osmotolerance of economically important plants and microorganisms.

show abstract

“…Expression of enaA was upregulated approximately 31-fold in the ⌬cnaA cchA re strain after salt stress treatment compared with the non-salt-treated strain. However, the expression of two other sodium transporter genes, nhnA and trkA (50)(51)(52), showed no significant differences among the tested strains when treated with 800 mM NaCl. These results suggested that increased expression of enaA may bypass the requirement for calcineurin in the ⌬cnaA cchA re strain under salt stress.…”

Section: Figmentioning

confidence: 86%

Calcineurin and Calcium Channel CchA Coordinate the Salt Stress Response by Regulating Cytoplasmic Ca ²⁺ Homeostasis in Aspergillus nidulans

Wang

Liu

Qian

et al. 2016

Appl Environ Microbiol

View full text Add to dashboard Cite

The eukaryotic calcium/calmodulin-dependent protein phosphatase calcineurin is crucial for the environmental adaption of fungi. However, the mechanism of coordinate regulation of the response to salt stress by calcineurin and the high-affinity calcium channel CchA in fungi is not well understood. Here we show that the deletion of cchA suppresses the hyphal growth defects caused by the loss of calcineurin under salt stress in Aspergillus nidulans. Additionally, the hypersensitivity of the ⌬cnaA strain to extracellular calcium and cell-wall-damaging agents can be suppressed by cchA deletion. T o rapidly sense and respond to different environmental conditions, organisms have evolved signaling pathways to coordinate growth, proliferation, and metabolism (1-6). Among them, the calcium-mediated signaling pathway plays an important regulatory role in various physiological processes, such as cell cycle, cytoskeletal rearrangement, ion homeostasis, and stress response (7-10). Calcium homeostasis systems are highly regulated pathways used by cells to maintain cytoplasmic Ca 2ϩ concentrations ([Ca 2ϩ ] c )within an optimal range in the cytosol and other organelles (11)(12)(13)(14). The rise and fall of free [Ca 2ϩ ] c can be directly sensed, decoded, and retransmitted to cellular targets, such as the Ca 2ϩ /calmodulin-dependent protein phosphatase calcineurin, which is highly conserved from yeasts to humans and mediates many important cellular processes (15,16).Calcineurin is a member of the serine-threonine-specific protein phosphatase (PP) family. It differs from other phosphatases in its metal ion requirements, range of substrate specificity, and cellular regulation (17). Calcineurin exists as a heterodimer of catalytic subunits (CnA) and regulatory subunits (CnB) (18,19), and the CnA subunit contains the catalytic domain and three regulatory domains, including the CnB-binding, calmodulin-bind-

show abstract

Potassium and sodium uptake systems in fungi. The transporter diversity of Magnaporthe oryzae

Cited by 49 publications

References 53 publications

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

Calcineurin and Calcium Channel CchA Coordinate the Salt Stress Response by Regulating Cytoplasmic Ca ²⁺ Homeostasis in Aspergillus nidulans

Contact Info

Product

Resources

About

Potassium and sodium uptake systems in fungi. The transporter diversity of Magnaporthe oryzae

Cited by 49 publications

References 53 publications

Coordination of K + Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Coordination of K + Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

Calcineurin and Calcium Channel CchA Coordinate the Salt Stress Response by Regulating Cytoplasmic Ca 2+ Homeostasis in Aspergillus nidulans

Contact Info

Product

Resources

About

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Coordination of K ⁺ Transporters in Neurospora: TRK1 Is Scarce and Constitutive, while HAK1 Is Abundant and Highly Regulated

Calcineurin and Calcium Channel CchA Coordinate the Salt Stress Response by Regulating Cytoplasmic Ca ²⁺ Homeostasis in Aspergillus nidulans