title: The translationally controlled tumor protein is a novel calcium binding protein of the human placenta and regulates calcium handling in trophoblast cells.
abstract: The translationally controlled tumor protein (TPT1, also known as TCTP) is a highly conserved, abundantly expressed protein found in mammals as well as in a wide range of other organisms of both the animal and plant kingdom. Initially considered as a growth-related protein, later studies showed TPT1 is endowed with multiple biological activities, including calcium binding. The present study aimed to evaluate the expression of TPT1 in the human placenta and to examine the functional role of the protein in the calcium binding and homeostasis of trophoblast cells. Samples were analyzed by Western blot, reverse transcription-polymerase chain reaction and immunohistochemistry. The effect of TPT1 knockdown by small interfering RNA (siRNA) on calcium uptake and buffering was assessed in the HTR-8/SVneo cell line. TPT1 protein and mRNA were detected in first-trimester and term placenta. In the tissue, TPT1 was localized in the villous trophoblast. TPT1 expression significantly increased during gestation, with the higher protein and mRNA levels reached at term. Recombinant placental TPT1 bound calcium in vitro, while downregulation of the protein levels by siRNA in HTR-8/SVneo cells was associated with a reduced cellular calcium-uptake activity and buffering capacity. These data demonstrate, for the first time, the expression of TPT1 in the human placenta and support a direct role of the protein in placental calcium transport.
authors.affiliation: Department of Human Pathology and Oncology, University of Siena, Italy. arcuri@unis.it
authors.forename: Felice
authors.initials: F
authors.lastname: Arcuri
authors.forename: Stefania
authors.initials: S
authors.lastname: Papa
authors.forename: Antonella
authors.initials: A
authors.lastname: Meini
authors.forename: Antonietta
authors.initials: A
authors.lastname: Carducci
authors.forename: Roberta
authors.initials: R
authors.lastname: Romagnoli
authors.forename: Laura
authors.initials: L
authors.lastname: Bianchi
authors.forename: Maria Giovanna
authors.initials: MG
authors.lastname: Riparbelli
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Sanchez
authors.forename: Mitri
authors.initials: M
authors.lastname: Palmi
authors.forename: Piero
authors.initials: P
authors.lastname: Tosi
authors.forename: Marcella
authors.initials: M
authors.lastname: Cintorino
mesh_terms: D001692:Biological Transport; D014408:Biomarkers, Tumor; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011264:Pregnancy Trimesters; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014327:Trophoblasts / Q000378:metabolism*; D000090324:Tumor Protein, Translationally-Controlled 1
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C000715647:TPT1 protein, human; D000090324:Tumor Protein, Translationally-Controlled 1; D002118:Calcium