title: Analysis of the extracellular matrix vesicle proteome in mineralizing osteoblasts.
abstract: Many key processes central to bone formation and homeostasis require the involvement of osteoblasts, cells responsible for accumulation and mineralization of the extracellular matrix (ECM). During this complex and only partially understood process, osteoblasts generate and secrete matrix vesicles (MVs) into the ECM to initiate mineralization. Although they are considered an important component of mineralization process, MVs still remain a mystery. To better understand their function and biogenesis, a proteomic analysis of MVs has been conducted. MVs were harvested by two sample preparation approaches and mass spectrometry was utilized for protein identification. A total of 133 proteins were identified in common from the two MV preparations, among which were previously known proteins, such as annexins and peptidases, along with many novel proteins including a variety of enzymes, osteoblast-specific factors, ion channels, and signal transduction molecules, such as 14-3-3 family members and Rab-related proteins. To compare the proteome of MV with that of the ECM we conducted a large-scale proteomic analysis of collagenase digested mineralizing osteoblast matrix. This analysis resulted in the identification of 1,327 unique proteins. A comparison of the proteins identified from the two MV preparations with the ECM analysis revealed 83 unique, non-redundant proteins identified in all three samples. This investigation represents the first systematic proteomic analysis of MVs and provides insights into both the function and origin of these important mineralization-regulating vesicles.
authors.affiliation: Laboratory of Proteomics and Analytical Technologies, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xiao
authors.forename: Corinne E
authors.initials: CE
authors.lastname: Camalier
authors.forename: Kunio
authors.initials: K
authors.lastname: Nagashima
authors.forename: King C
authors.initials: KC
authors.lastname: Chan
authors.forename: David A
authors.initials: DA
authors.lastname: Lucas
authors.forename: M Jason
authors.initials: MJ
authors.lastname: de la Cruz
authors.forename: Michelle
authors.initials: M
authors.lastname: Gignac
authors.forename: Stephen
authors.initials: S
authors.lastname: Lockett
authors.forename: Haleem J
authors.initials: HJ
authors.lastname: Issaq
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Veenstra
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Conrads
authors.forename: George R
authors.initials: GR
authors.lastname: Beck
mesh_terms: D000818:Animals; D001846:Bone Development / Q000502:physiology; D001857:Bone Matrix / Q000378:metabolism* / Q000648:ultrastructure; D002113:Calcification, Physiologic / Q000502:physiology*; D002460:Cell Line; D022162:Cytoplasmic Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D013058:Mass Spectrometry; D051379:Mice; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010006:Osteoblasts / Q000378:metabolism* / Q000648:ultrastructure; D010012:Osteogenesis / Q000502:physiology; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics
chemical_list: D016326:Extracellular Matrix Proteins; D020543:Proteome