title: Cloning and characterization of a p53 and DNA damage down-regulated gene PIQ that codes for a novel calmodulin-binding IQ motif protein and is up-regulated in gastrointestinal cancers.
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.
authors.affiliation: Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, New York 13210, USA.
authors.forename: Xiuquan
authors.initials: X
authors.lastname: Luo
authors.forename: Qin
authors.initials: Q
authors.lastname: He
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: M Saeed
authors.initials: MS
authors.lastname: Sheikh
mesh_terms: D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics; D002147:Calmodulin / Q000378:metabolism; D002148:Calmodulin-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D016384:Consensus Sequence; D004249:DNA Damage; D015972:Gene Expression Regulation, Neoplastic; D045325:HCT116 Cells; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D016415:Sequence Alignment; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; C498171:IQCB1 protein, human; D011518:Proto-Oncogene Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53