Source:http://linkedlifedata.com/resource/pubmed/id/14622290
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
21
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pubmed:dateCreated |
2003-11-18
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pubmed:abstractText |
The phylogenetically conserved eukaryotic translation initiation factor 5A (eIF5A) is the only known cellular protein to contain the post-translationally derived amino acid hypusine [Nepsilon-(4-amino-2-hydroxybutyl)lysine]. Both eIF5A and its hypusine modification are essential for sustained cell proliferation. Normally only one eIF5A protein is expressed in human cells. Recently, we identified a second human EIF5A gene that would encode an isoform (eIF5A-2) of 84% sequence identity. Overexpression of eIF5A-2 mRNA in certain human cancer cells, in contrast to weak normal expression limited to human testis and brain, suggests EIF5A2 as a potential oncogene. However, eIF5A-2 protein has not been described in human or mammalian cells heretofore. Here, we describe the identification of eIF5A-2 protein in human colorectal and ovarian cancer lines, SW-480 and UACC-1598, that overexpress eIF5A-2 mRNAs. Functional characterization of the human isoforms revealed that either human EIF5A gene can complement growth of a yeast strain in which the yeast EIF5A genes were disrupted. This indicates functional similarity of the human isoforms in yeast and suggests that eIF5A-2 has an important role in eukaryotic cell survival similar to that of the ubiquitous eIF5A-1. Detectable structural differences were also noted, including lack of immunological cross-reactivity, formation of different complexes with deoxyhypusine synthase, and Km values (1.5 +/- 0.2 vs. 8.3 +/- 1.4 microm for eIF5A-1 and -2, respectively) as substrates for deoxyhypusine synthase in vitro. These physical characteristics and distinct amino acid sequences in the C-terminal domain together with differences in gene expression patterns imply differentiated, tissue-specific functions of the eIF5A-2 isoform in the mammalian organism and in cancer.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
270
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
4254-63
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:14622290-Amino Acid Sequence,
pubmed-meshheading:14622290-Base Sequence,
pubmed-meshheading:14622290-Cell Line, Tumor,
pubmed-meshheading:14622290-Cloning, Molecular,
pubmed-meshheading:14622290-DNA, Complementary,
pubmed-meshheading:14622290-DNA Primers,
pubmed-meshheading:14622290-Electrophoretic Mobility Shift Assay,
pubmed-meshheading:14622290-Female,
pubmed-meshheading:14622290-Humans,
pubmed-meshheading:14622290-Molecular Sequence Data,
pubmed-meshheading:14622290-Peptide Initiation Factors,
pubmed-meshheading:14622290-RNA Processing, Post-Transcriptional,
pubmed-meshheading:14622290-Reverse Transcriptase Polymerase Chain Reaction,
pubmed-meshheading:14622290-Saccharomyces cerevisiae,
pubmed-meshheading:14622290-Sequence Homology, Amino Acid
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pubmed:year |
2003
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pubmed:articleTitle |
Identification and characterization of eukaryotic initiation factor 5A-2.
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pubmed:affiliation |
Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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