Specificity of the accumulation of mRNAs and proteins of the plasma membrane and tonoplast aquaporins in radish organs

Suga, Shinobu; Imagawa, Shino; Maeshima, Masayoshi

doi:10.1007/s004250000396

Cited by 78 publications

(60 citation statements)

References 44 publications

(60 reference statements)

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“…Neither the RD28 protein from Arabidopsis nor the mRNA of BnPIP1 from Brassica napus was detectable in dry seeds (Daniels et al, 1994;Gao et al, 1999). In dry seeds of radish transcripts of both a PIP2 homologue (PAQ2) and a PIP1 homologue (PAQ1) were undetectable (Suga et al, 2001). We found the mRNA of PsPIP1-1 and/or its possible close homologues to be abundantly present in the dry pea seed (Figure 3).…”

Section: Abundant Transcripts Of a Pip1 Homologue In The Dry Seedmentioning

confidence: 76%

“…Transcripts of TIP1-members have never been detected in dry seeds (Ludevid et al, 1992;Gao et al, 1999;Suga et al, 2001). In the cotyledons of the pea seed hybridization signals of the PsTIP1-1 probe disappeared during seed fill, were undetectable in the dry seed, and reappeared during germination (Figures 2 and 3).…”

Section: Some Tip1 Members (γ Tips) Are Highly Expressed In Tissues Wmentioning

confidence: 95%

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Members of the aquaporin family in the developing pea seed coat include representatives of the PIP, TIP, and NIP subfamilies

et al. 2003

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Water and nutrients required by developing seeds are mainly supplied by the phloem and have to be released from a maternal parenchyma tissue before being utilized by the filial tissues of embryo and endosperm. To identify aquaporins that could be involved in this process four full-length cDNAs were cloned and sequenced from a cDNA library of developing seed coats of pea (Pisum sativum L.). The cDNA of PsPIP1-1 appeared to be identical to that of clone 7a/TRG-31, a turgor-responsive gene cloned previously from pea roots. PsPIP1-1, PsPIP2-1, and PsTIP1-1, or their possible close homologues, were also expressed in cotyledons of developing and germinating seeds, and in roots and shoots of seedlings, but transcripts of PsNIP-1 were only detected in the seed coat. In mature dry seeds, high hybridization signals were observed with the probe for PsPIP1-1, but transcripts of PsPIP2-1, PsTIP1-1, and PsNIP-1 were not detected. Functional characterization after heterologous expression in Xenopus oocytes showed that PsPIP2-1 and PsTIP1-1 are aquaporins whereas PsNIP-1 is an aquaglyceroporin. PsNIP-1, like several other NIPs, contains a tryptophan residue corresponding with Trp-48 in GlpF (the glycerol facilitator of Escherichia coli) that borders the selectivity filter in the permeation channel. It is suggested that PsPIP1-1 and/or its possible close homologues could play a role in water absorption during seed imbibition, and that PsPIP2-1, possibly together with PsPIP1-1, could be involved in the release of phloem water from the seed coat symplast, which is intimately connected with the release of nutrients for the embryo.Abbreviations: MIPs, major intrinsic proteins; NIPs, nodulin 26-like intrinsic proteins; PIPs, plasma membrane intrinsic proteins; SIPs, small, basic intrinsic proteins; TIPs, tonoplast intrinsic proteins

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Section: Abundant Transcripts Of a Pip1 Homologue In The Dry Seedmentioning

confidence: 76%

Section: Some Tip1 Members (γ Tips) Are Highly Expressed In Tissues Wmentioning

confidence: 95%

Members of the aquaporin family in the developing pea seed coat include representatives of the PIP, TIP, and NIP subfamilies

et al. 2003

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“…The failure to demonstrate AtTIP2;1 functionality in this approach might have several causes. (1) Enhanced mRNA levels of AtTIP2;1 might have been compensated for by posttranscriptional down-regulation; indeed, posttranscriptional regulation of tonoplast aquaporins has been indicated in radish (Suga et al, 2001). Moreover, MIP activity has been shown to be controlled by phosphorylation (Maurel et al, 1995;Johansson et al, 1998;Niemietz and Tyerman, 2000), and AtTIP2;1 also exposes putative phosphorylation sites to the cytoplasm.…”

mentioning

confidence: 99%

Tonoplast Intrinsic Proteins AtTIP2;1 and AtTIP2;3 Facilitate NH3 Transport into the Vacuole

Loqué

Ludewig²,

Yuan³

et al. 2005

Plant Physiology

310

212

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While membrane transporters mediating ammonium uptake across the plasma membrane have been well described at the molecular level, little is known about compartmentation and cellular export of ammonium. (The term ammonium is used to denote both NH 3 and NH 4 1 and chemical symbols are used when specificity is required.) We therefore developed a yeast (Saccharomyces cerevisiae) complementation approach and isolated two Arabidopsis (Arabidopsis thaliana) genes that conferred tolerance to the toxic ammonium analog methylammonium in yeast. Both genes, AtTIP2;1 and AtTIP2;3, encode aquaporins of the tonoplast intrinsic protein subfamily and transported methylammonium or ammonium in yeast preferentially at high medium pH. AtTIP2;1 expression in Xenopus oocytes increased 14 C-methylammonium accumulation with increasing pH. AtTIP2;1-and AtTIP2;3-mediated methylammonium detoxification in yeast depended on a functional vacuole, which was in agreement with the subcellular localization of green fluorescent protein-fusion proteins on the tonoplast in planta. Transcript levels of both AtTIPs were influenced by nitrogen supply but did not follow those of the nitrogen-derepressed ammonium transporter gene AtAMT1;1. Transgenic Arabidopsis plants overexpressing AtTIP2;1 did not show altered ammonium accumulation in roots after ammonium supply, although AtTIP2;1 mRNA levels in wild-type plants were up-regulated under these conditions. This study shows that AtTIP2;1 and AtTIP2;3 can mediate the extracytosolic transport of methyl-NH 2 and NH 3 across the tonoplast membrane and may thus participate in vacuolar ammonium compartmentation.As a major form of reduced nitrogen, ammonium plays a key role in the metabolism of most cells. (The term ammonium is used to denote both NH 3 and NH 4 + and chemical symbols are used when specificity is required.) Ammonium is a preferential nitrogen source for many microorganisms and plants. It represents the key compound for the transition of inorganic to organic nitrogen and vice versa, and it is a major form for nitrogen retrieval after unavoidable losses from deamination or transamination processes. Moreover, ammonium triggers the induction of nitrogen assimilatory genes (Ishiyama et al., 2004) and leads to changes in root morphology (Drew, 1975). It is unclear how its external and/or internal concentration is sensed by plant cells, but an NH 4

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“…Once a protein is involved, the cell has the ability to regulate its abundance (transcriptional or post-transcriptional) or to modulate its activity [2,32]. Water permeability of the plasma membrane and tonoplast through the aquaporins depends on their quantity, activity, and substrate specificity [33]. In part because of this very high diversity, the knowledge about plant aquaporin expression and subcellular localization is far from complete [34].…”

Section: Diversity Of Plant Aquaporinsmentioning

confidence: 99%

“…Therefore, the expression of aquaporin genes may be independently regulated in an organ and stage-specific manner, while the amount of aquaporin protein can be regulated at the translational level and by the rate of protein turnover [13,33,43,44]. Meanwhile there are numerous reports providing clear evidence that the abundance of aquaporins can be regulated by developmental and environmental factors [6,13,32].…”

Section: Aquaporin Gene Expression and Diurnal Fluctuationsmentioning

confidence: 99%

Aquaporin structure–function relationships: Water flow through plant living cells

Zhao

Shao

Chu

2008

Colloids and Surfaces B: Biointerfaces

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Plant aquaporins play an important role in water uptake and movement-an aquaporin that opens and closes a gate that regulates water movement in and out of cells. Some plant aquaporins also play an important role in response to water stress. Since their discovery, advancing knowledge of their structures and properties led to an understanding of the basic features of the water transport mechanism and increased illumination to water relations. Meanwhile, molecular and functional characterization of aquaporins has revealed the significance of their regulation in response to the adverse environments such as salinity and drought. This paper reviews the structure, species diversity, physiology function, regulation of plant aquaporins, and the relations between environmental factors and plant aquaporins. Complete understanding of aquaporin function and regulation is to integrate those mechanisms in time and space and to well regulate the permeation of water across biological membranes under changing environmental and developmental conditions.

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Specificity of the accumulation of mRNAs and proteins of the plasma membrane and tonoplast aquaporins in radish organs

Cited by 78 publications

References 44 publications

Members of the aquaporin family in the developing pea seed coat include representatives of the PIP, TIP, and NIP subfamilies

Members of the aquaporin family in the developing pea seed coat include representatives of the PIP, TIP, and NIP subfamilies

Tonoplast Intrinsic Proteins AtTIP2;1 and AtTIP2;3 Facilitate NH3 Transport into the Vacuole

Aquaporin structure–function relationships: Water flow through plant living cells

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