Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2003-7-9
pubmed:databankReference
pubmed:abstractText
Mechanisms are required by all organisms to maintain the concentration of essential heavy metals (e.g. Zn and Cu) within physiological limits and to minimise the detrimental effects of non-essential heavy metals (e.g. Cd). Heavy-metal P-type ATPases (HMAs) are a subgroup of the P-type ATPase superfamily that may contribute to metal homeostasis in plants. We cloned and characterised a member of this family, AtHMA4, from Arabidopsis thaliana that clusters with the Zn/Co/Cd/Pb subclass of HMAs on phylogenetic analysis. Sequencing of the AtHMA4 cDNA showed that it contained the conserved motifs found in all P-type ATPases and also motifs that are characteristic of heavy-metal ATPases. Escherichia coli mutants defective in the HMAs, CopA and ZntA, were used in functional complementation studies. AtHMA4 was able to restore growth at high [Zn] in the zntA mutant but not at high [Cu] in the copA mutant, suggesting a role in zinc transport. Heterologous expression of AtHMA4 in Saccharomyces cerevisiae made the yeast more resistant to Cd but did not affect sensitivity to other metals compared with vector-transformed controls. The organ specificity of AtHMA4 was analysed in Arabidopsis and showed that AtHMA4 was expressed in a range of tissues with highest expression in roots. AtHMA4 was upregulated in roots exposed to elevated levels of Zn and Mn but downregulated by Cd. Possible physiological roles of this transporter in Arabidopsis are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
164-76
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12848823-Adenosine Triphosphatases, pubmed-meshheading:12848823-Amino Acid Sequence, pubmed-meshheading:12848823-Arabidopsis, pubmed-meshheading:12848823-Arabidopsis Proteins, pubmed-meshheading:12848823-Cadmium, pubmed-meshheading:12848823-Cloning, Molecular, pubmed-meshheading:12848823-Copper, pubmed-meshheading:12848823-DNA, Complementary, pubmed-meshheading:12848823-Escherichia coli, pubmed-meshheading:12848823-Gene Expression Regulation, Enzymologic, pubmed-meshheading:12848823-Gene Expression Regulation, Plant, pubmed-meshheading:12848823-Lead, pubmed-meshheading:12848823-Metals, Heavy, pubmed-meshheading:12848823-Molecular Sequence Data, pubmed-meshheading:12848823-Phylogeny, pubmed-meshheading:12848823-Saccharomyces cerevisiae, pubmed-meshheading:12848823-Sequence Analysis, DNA, pubmed-meshheading:12848823-Sequence Homology, Amino Acid, pubmed-meshheading:12848823-Substrate Specificity, pubmed-meshheading:12848823-Zinc
pubmed:year
2003
pubmed:articleTitle
Functional expression of AtHMA4, a P1B-type ATPase of the Zn/Co/Cd/Pb subclass.
pubmed:affiliation
School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't