Comparative Functional Features of Plant Potassium HvHAK1 and HvHAK2 Transporters

Senn, María Eugenia; Rubio, Francisco; Bañuelos, María Antonia; Rodríguez‐Navarro, Alonso

doi:10.1074/jbc.m108129200

Cited by 89 publications

(82 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result was unexpected because although root tips are comprised of many different cell types, root hairs are of a single cell type. The plethora of AtKT/KUPs expressed in the root hairs may provide indirect support for the suggestion put forward by Senn et al (2001) that the AtKT/ KUPs are localized to different membranes, such as the plasma and tonoplast membrane (Senn et al, 2001;Banuelos et al, 2002). Based on functional data showing a difference in the optimal pH for uptake and phylogenetic groupings, AtKT/HAK/KUPs from both barley (Hordeum vulgare) and rice were also suggested to be localized on the vacuolar membrane.…”

Section: Complementation and Rbmentioning

confidence: 88%

“…It has been suggested that some of the KT/HAK/KUPs mediate plasma membrane uptake, whereas others are involved in vacuolar transport (Senn et al, 2001). Two studies of AtKT/KUP mutants in Arabidopsis show that mutations cause reduced cell expansion (Rigas et al, 2001;Elumalai et al, 2002).…”

mentioning

confidence: 99%

“…Only recently have these transporters been identified and studied in plants (Quintero and Blatt, 1997;Santa-Maria et al, 1997;Fu and Luan, 1998;Kim et al, 1998). Studies in plants and microorganisms make it clear that these transporters have a wide variety of functional properties, including both high-and low-affinity K ϩ transport (Fu and Luan, 1998;Senn et al, 2001). KT/HAK/KUP gene expression often is found in all tissues, which have been tested in a wide range of species (Kim et al, 1998;Rigas et al, 2001;Langer et al, 2002;Su et al, 2002).…”

mentioning

confidence: 99%

“…Cells were harvested when OD 600 reached 1.0 and washed four times with deionized water. For complementation tests, 10 L of cells resuspended in water was placed on minimal media plates (Senn et al, 2001;5 …”

mentioning

confidence: 99%

See 3 more Smart Citations

Expression of KT/KUP Genes in Arabidopsis and the Role of Root Hairs in K+ Uptake

2004

View full text Add to dashboard Cite

Potassium (K ϩ ) is essential for plant growth and is the most abundant cation in plants, making up 3% to 5% of the plant's total dry weight (Marschner, 1995). K ϩ is involved in enzyme function, the maintenance of turgor pressure, leaf, and stomatal movement, and cell elongation (Kochian and Lucas, 1988;Schroeder et al., 1994; Maathuis and Sanders, 1996; Maathuis et al., 1997;Very and Sentenac, 2003). Plants have multiple mechanisms for K ϩ uptake from soil and translocation to various plant tissues to help them respond to changing environmental conditions and the varying K ϩ requirements in different tissues. Epstein and colleagues provided the first evidence of the operation of at least two (high-and lowaffinity) K ϩ uptake systems in plants (Epstein et al., 1963; Kochian and Lucas, 1988). The two transport systems were proposed to play roles in uptake that correspond with external K ϩ concentrations. More recently, it has been shown that there is functional overlap between high-and low-affinity uptake mechanisms (Hirsch et al., 1998;Santa-Maria et al., 2000). In addition to the uptake mechanisms' differences in affinity, the high-affinity uptake mechanisms have been shown to be inducible, whereas the low-affinity systems may be constitutive (Glass, 1976(Glass, , 1983 Fernando et al., 1990). Root epidermal cells play an important role in high-and low-affinity K ϩ acquisition (Kochian and Lucas, 1983;Gassmann and Schroeder, 1994; Jungk, 2001). At least two K ϩ channels, a nonselective cation channel and a K ϩ transporter, have been shown to be active in root epidermal cells; therefore, it is likely that more than two different proteins are involved in high-and low-affinity K ϩ uptake (Very and Sentenac, 2003).It is also likely that the translocation of K ϩ involves multiple transport proteins. It has been shown that a specific K ϩ channel is involved in xylem loading, but other proteins are implicated in this process because the deletion of this channel only partially reduced xylem K ϩ concentrations (Gaymard et al., 1998). Many steps are involved in the radial movement of K ϩ from the surface of the root to the xylem; the molecular details of this process are not understood (Tester and Leigh, 2001). After K ϩ is released into the xylem, it moves to the shoots. Then, it must be unloaded in the leaves. K ϩ is also retranslocated from leaves to other parts of the plant, such as roots or other sink tissues. Retranslocation occurs via the phloem, where K ϩ channels have been identified as being involved in phloem loading (Deeken et al., 2002; Philippar et al., 2003).There are five major families of K ϩ transporters that have been identified in Arabidopsis (Maser et al., 2001). The contribution of many of these transporters to cellular or whole-plant K ϩ homeostasis is not yet clear. The largest gene family of K ϩ transporters in Arabidopsis is the AtKT/KUP family; 13 genes are encoded by this family (Very and Sentenac, 2003). These transporters were originally identified in Escherichia coli as KUPs (K ϩ uptak...

show abstract

Section: Complementation and Rbmentioning

confidence: 88%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Expression of KT/KUP Genes in Arabidopsis and the Role of Root Hairs in K+ Uptake

2004

View full text Add to dashboard Cite

show abstract

“…The translocation of Na + into vacuoles by vacuolarlocalized Na + /H + antiporters, such as At-NHX, provides another mechanism to prevent the toxic accumulation of Na + in the cytoplasm (Apse et al, 1999;Yokoi et al, 2002;Apse et al, 2003;An et al, 2007;Barragán et al, 2012). Voltage-dependent cation channels (HKT and KUP), proton pumps (the H + -ATPase and the H + -pyrophosphatase) and a Ca 2+ /H + antiporter (VCX1) also play roles in Na + compartmentation (Assmann and Haubrick, 1996;Serrano et al, 1999;Gaxiola et al, 2001;Senn et al, 2001;Berthomieu et al, 2003;Rus et al, 2004;Davenport et al, 2007;Fuglsang et al, 2007;Yang et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

UBIQUITIN-SPECIFIC PROTEASE16 Modulates Salt Tolerance in Arabidopsis by Regulating Na+/H+ Antiport Activity and Serine Hydroxymethyltransferase Stability

et al. 2012

View full text Add to dashboard Cite

Protein ubiquitination is a reversible process catalyzed by ubiquitin ligases and ubiquitin-specific proteases (UBPs). We report the identification and characterization of UBP16 in Arabidopsis thaliana. UBP16 is a functional ubiquitin-specific protease and its enzyme activity is required for salt tolerance. Plants lacking UBP16 were hypersensitive to salt stress and accumulated more sodium and less potassium. UBP16 positively regulated plasma membrane Na + /H + antiport activity. Through yeast two-hybrid screening, we identified a putative target of UBP16, SERINE HYDROXYMETHYLTRANSFERASE1 (SHM1), which has previously been reported to be involved in photorespiration and salt tolerance in Arabidopsis. We found that SHM1 is degraded in a 26S proteasome-dependent process, and UBP16 stabilizes SHM1 by removing the conjugated ubiquitin. Ser hydroxymethyltransferase activity is lower in the ubp16 mutant than in the wild type but higher than in the shm1 mutant. During salt stress, UBP16 and SHM1 function in preventing cell death and reducing reactive oxygen species accumulation, activities that are correlated with increasing Na + /H + antiport activity. Overexpression of SHM1 in the ubp16 mutant partially rescues its salt-sensitive phenotype. Taken together, our results suggest that UBP16 is involved in salt tolerance in Arabidopsis by modulating sodium transport activity and repressing cell death at least partially through modulating SMH1stability and activity.

show abstract

Using Heterologous Expression Systems to Characterize Potassium and Sodium Transport Activities

Rodríguez

Benito

Cagnac

2012

Methods in Molecular Biology

View full text Add to dashboard Cite

The expression of plant transporters in simple well-characterized cell systems is an irreplaceable technique for gaining insights into the kinetic and energetic features of plant transporters. Among all the available expression systems, yeast cells offer the highest simplicity and have the capacity to mimic the in vivo properties of plant transporters. Here, we describe the use of yeast mutants to express K(+) and Na(+) plant transporters and discuss some experimental problems that can produce misleading results.

show abstract

Comparative Functional Features of Plant Potassium HvHAK1 and HvHAK2 Transporters

Cited by 89 publications

References 40 publications

Expression of KT/KUP Genes in Arabidopsis and the Role of Root Hairs in K+ Uptake

Expression of KT/KUP Genes in Arabidopsis and the Role of Root Hairs in K+ Uptake

UBIQUITIN-SPECIFIC PROTEASE16 Modulates Salt Tolerance in Arabidopsis by Regulating Na+/H+ Antiport Activity and Serine Hydroxymethyltransferase Stability

Using Heterologous Expression Systems to Characterize Potassium and Sodium Transport Activities

Contact Info

Product

Resources

About