title: Analysis of the interaction of calcitriol with the disulfide isomerase ERp57.
abstract: Calcitriol, the active form of vitamin D3, can regulate the gene expression through the binding to the nuclear receptor VDR, but it can also display nongenomic actions, acting through a membrane-associated receptor, which has been discovered as the disulfide isomerase ERp57. The aim of our research is to identify the binding sites for calcitriol in ERp57 and to analyze their interaction. We first studied the interaction through bioinformatics and fluorimetric analyses. Subsequently, we focused on two protein mutants containing the predicted interaction domains with calcitriol: abb'-ERp57, containing the first three domains, and a'-ERp57, the fourth domain only. To consolidate the achievements we used the calorimetric approach to the whole protein and its mutants. Our results allow us to hypothesize that the interaction with the a' domain contributes to a greater extent than the other potential binding sites to the dissociation constant, calculated as a Kd of about 10-9M.
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Gaucci
authors.affiliation: Stem Cell Lab - Department of Molecular Medicine - Sapienza Università di Roma, Viale Regina Elena 324, 00161, Rome, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Raimondo
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Grillo
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Cervoni
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.|Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Altieri
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Nittari
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.|Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Eufemi
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Chichiarelli
mesh_terms: D002117:Calcitriol / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D011487:Protein Conformation; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000378:metabolism*; D017510:Protein Folding
chemical_list: D019704:Protein Disulfide-Isomerases; C085868:PDIA3 protein, human; D002117:Calcitriol