Abstract
We have identified a p53 and DNA damage-regulated gene that encodes a novel IQ motif protein, which we have named p53 and DNA damage-regulated IQ motif protein (PIQ). PIQ has two isoforms, long (PIQ-L) and short (PIQ-S), and both bind to calmodulin in the presence and absence of calcium. PIQ expression is down-regulated by p53 and DNA damage-inducing agents, whereas PIQ itself represses the expression of p53 up-regulated modulator of apoptosis that is a key mediator of p53-induced apoptosis. Thus, PIQ is a novel protein that may function to bridge a crosstalk between p53 and calmodulin-regulated cellular processes. We further show that PIQ expression is up-regulated in a number of primary colorectal and gastric tumors when compared with matching normal tissues, suggesting that PIQ may be involved in tumorigenesis and could serve as a valuable diagnostic/prognostic marker for gastrointestinal tumors.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Apoptosis Regulatory Proteins / biosynthesis
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Apoptosis Regulatory Proteins / genetics
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Calmodulin / metabolism
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Calmodulin-Binding Proteins / genetics*
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Calmodulin-Binding Proteins / metabolism
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Cell Line, Tumor
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Cloning, Molecular
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Colorectal Neoplasms / genetics*
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Colorectal Neoplasms / metabolism
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Consensus Sequence
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DNA Damage*
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Gene Expression Regulation, Neoplastic
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HCT116 Cells
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Humans
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Lung Neoplasms / genetics
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Lung Neoplasms / metabolism
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Molecular Sequence Data
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / genetics
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Sequence Alignment
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Stomach Neoplasms / genetics*
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Stomach Neoplasms / metabolism
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Transfection
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Tumor Suppressor Protein p53 / genetics
Substances
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Apoptosis Regulatory Proteins
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BBC3 protein, human
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Calmodulin
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Calmodulin-Binding Proteins
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IQCB1 protein, human
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Proto-Oncogene Proteins
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TP53 protein, human
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Tumor Suppressor Protein p53