Linked Life Data

14988489

Source:http://linkedlifedata.com/resource/pubmed/id/14988489

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2004-2-27
pubmed:databankReference
pubmed:abstractText
In NADP-malic enzyme-type C(4) plants such as maize (Zea mays L.), efficient transport of oxaloacetate and malate across the inner envelope membranes of chloroplasts is indispensable. We isolated four maize cDNAs, ZmpOMT1 and ZmpDCT1 to 3, encoding orthologs of plastidic 2-oxoglutarate/malate and general dicarboxylate transporters, respectively. Their transcript levels were upregulated by light in a cell-specific manner; ZmpOMT1 and ZmpDCT1 were expressed in the mesophyll cell (MC) and ZmpDCT2 and 3 were expressed in the bundle sheath cell (BSC). The recombinant ZmpOMT1 protein expressed in yeast could transport malate and 2-oxoglutarate but not glutamate. By contrast, the recombinant ZmpDCT1 and 2 proteins transported 2-oxoglutarate and glutamate at similar affinities in exchange for malate. The recombinant proteins could also transport oxaloacetate at the same binding sites as those for the dicarboxylates. In particular, ZmpOMT1 transported oxaloacetate at a higher efficiency than malate or 2-oxoglutarate. We also compared the activities of oxaloacetate transport between MC and BSC chloroplasts from maize leaves. The K(m) value for oxaloacetate in MC chloroplasts was one order of magnitude lower than that in BSC chloroplasts, and was close to that determined with the recombinant ZmpOMT1 protein. Southern analysis revealed that maize has a single OMT gene. These findings suggest that ZmpOMT1 participates in the import of oxaloacetate into MC chloroplasts in exchange for stromal malate. In BSC chloroplasts, ZmpDCT2 and/or ZmpDCT3 were expected to import malate that is transported from MC.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0032-0781
pubmed:author
pubmed:issnType
Print
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
187-200
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:14988489-Amino Acid Sequence, pubmed-meshheading:14988489-Base Sequence, pubmed-meshheading:14988489-Carrier Proteins, pubmed-meshheading:14988489-Chloroplasts, pubmed-meshheading:14988489-DNA, Complementary, pubmed-meshheading:14988489-Dicarboxylic Acid Transporters, pubmed-meshheading:14988489-Energy Metabolism, pubmed-meshheading:14988489-Gene Expression Regulation, Plant, pubmed-meshheading:14988489-Malates, pubmed-meshheading:14988489-Membrane Transport Proteins, pubmed-meshheading:14988489-Molecular Sequence Data, pubmed-meshheading:14988489-Oxaloacetate, pubmed-meshheading:14988489-Phylogeny, pubmed-meshheading:14988489-Plant Proteins, pubmed-meshheading:14988489-Recombinant Fusion Proteins, pubmed-meshheading:14988489-Sequence Homology, Amino Acid, pubmed-meshheading:14988489-Sequence Homology, Nucleic Acid, pubmed-meshheading:14988489-Zea mays
pubmed:year
2004
pubmed:articleTitle
Differentiation of dicarboxylate transporters in mesophyll and bundle sheath chloroplasts of maize.
pubmed:affiliation
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601 Japan. taniguti@agr.nagoya-u.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't