Affiliation: Department of Biomaterials, Osaka Dental University, 8-1 Kuzuhahanazono-cho, Hirakata-shi, Osaka 573-1121, Japan.
The noncollagenous proteins UACA, EXOSC9, and TMX2 were previously identified in bovine periosteal cells with a combination of mass spectrometry and immunohistochemistry. In this study, the proteins β-tubulin, F-box/leucinerich repeat protein 14 (FBXL14), and type 1 procollagen C-peptide were investigated in these cells. Peptides of β-tubulin and FBXL14 were detected with liquid chromatography tandem mass spectrometry, with protein sequence coverages of 2% and 3%, respectively. A two-dimensional protein electrophoretic map of the culture supernatant of bovine periosteal cells suggested that TMX2 was close to type 1 procollagen C-peptide in the cell aggregate. Therefore, an immunohistochemical analysis of β-tubulin, FBXL14, and type 1 procollagen C-peptide was performed. The bovine periosteal cells were positive for β-tubulin, FBXL14, and type 1 procollagen C-peptide. The noncollagenous proteins β-tubulin and FBXL14 were thus identified, like UACA, EXOSC9, and TMX2, in bovine periosteal cells. Type 1 procollagen C-peptide was only expressed in a subset of cells, whereas type 1 collagen was expressed ubiquitously. It is possible that type 1 procollagen C-peptide is associated with those noncollagenous proteins. This study demonstrates the utility of a technique combining MS and immunohistochemistry.