title: Label-free quantification proteomics reveals novel calcium binding proteins in matrix vesicles isolated from mineralizing Saos-2 cells.
abstract: Matrix vesicles (MVs) involved in the initiation of mineralization by deposition of hydroxyapatite (HA) in their lumen are released by the budding of mineralization-competent cells during skeletogenesis and bone development. To identify additional mineralization-related proteins, MVs were isolated from non-stimulated and stimulated Saos-2 cells in culture via an Exoquick™ approach and the corresponding proteomes were identified and quantified with label-free quantitative proteome technology. The isolated MVs were confirmed by electron microscopy, alkaline phosphatase activity (ALP), biomarkers, and mineral formation analyses. Label-free quantitative proteome analysis revealed that 19 calcium binding proteins (CaBPs), including Grp94, calnexin, calreticulin, calmodulin, and S100A4/A10, were up-regulated in MVs of Saos-2 cells upon stimulation of mineralization. This result provides new clues to study the mechanism of the initiation of MV-mediated mineralization.
authors.affiliation: Key Laboratory for Rare Disease Research of Shandong Province, Key Laboratory for Biotech Drugs of the Ministry of Health, Shandong Medical Biotechnological Center, Shandong Academy of Medical Sciences, Ji'nan, Shandong, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Zhou
authors.forename: Yazhou
authors.initials: Y
authors.lastname: Cui
authors.forename: Jing
authors.initials: J
authors.lastname: Luan
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhou
authors.forename: Genglin
authors.initials: G
authors.lastname: Zhang
authors.forename: Xiumei
authors.initials: X
authors.lastname: Zhang
authors.forename: Jinxiang
authors.initials: J
authors.lastname: Han
mesh_terms: D002135:Calcium-Binding Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D017886:Durapatite / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D006801:Humans; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D002135:Calcium-Binding Proteins; D017886:Durapatite