title: SPARC/osteonectin in mineralized tissue.
abstract: Secreted protein acidic and rich in cysteine (SPARC/osteonectin/BM40) is one of the most abundant non-collagenous protein expressed in mineralized tissues. This review will focus on elucidating functional roles of SPARC in bone formation building upon results from non-mineralized cells and tissues, the phenotype of SPARC-null bones, and recent discoveries of human diseases with either dysregulated expression of SPARC or mutations in the gene encoding SPARC that give rise to bone pathologies. The capacity of SPARC to influence pathways involved in extracellular matrix assembly such as procollagen processing and collagen fibril formation as well as the capacity to influence osteoblast differentiation and osteoclast activity will be addressed. In addition, the potential for SPARC to regulate cross-linking of extracellular matrix proteins by members of the transglutaminase family of enzymes is explored. Elucidating defined biological functions of SPARC in terms of bone formation and turnover are critical. Further insight into specific cellular mechanisms involved in the formation and homeostasis of mineralized tissues will lead to a better understanding of disease progression.
authors: Department of Oral Health Sciences, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, United States.
authors: Emilie M
authors: EM
authors: Rosset
authors: Department of Oral Health Sciences, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, United States; Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson Veterans Administration, VA Medical Center, Charleston, SC, United States.
authors: Amy D
authors: AD
authors: Bradshaw
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000502:physiology*; D002113:Calcification, Physiologic; D002454:Cell Differentiation; D005109:Extracellular Matrix / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D009154:Mutation; D010006:Osteoblasts / Q000166:cytology; D010010:Osteoclasts / Q000166:cytology; D010013:Osteogenesis Imperfecta / Q000235:genetics; D015676:Osteonectin / Q000235:genetics* / Q000378:metabolism*; D010024:Osteoporosis / Q000235:genetics; D011503:Transglutaminases / Q000378:metabolism
chemical_list: D015676:Osteonectin; C577241:SPARC protein, human; D011503:Transglutaminases
keywords: Collagen; Matricellular; Mineral; Osteoblast; Osteoclast