The relationship between Vitamin K and vitamin K-Dependent proteins and bone metabolism is not clearly understood. A vitamin K-dependent, bone specific protein of unknown function has been identified in all bones examined. This protein, called the bone Gla protein (BGP) or osteocalcin, is an abundant noncollagenous protein, and comprises approximately 1-2% of the total proteins present. Minute quantities are found in the circulation, and levels are altered in diseases such as osteoporosis and various metabolic bone diseases. In this application the role of vitamin K-dependent proteins in bone will be explored in experiments to: 1) Determine the number and relationship of all bone derived vitamin K dependent proteins, by searching for proteins antigenically related to BGP or which contain the vitamin K-dependent Gamma -carboxy glutamate. 2) Establish the sequence of events, and factors which control the biosynthesis and secretion of bone G1a protein using cloned rat osteosarcome cells. 3) Explore the localization and distribution of bone G1a protein in bone matrix using purified antibody and immunochemical methods, and 4) The potential role of bone G1a protein as an etiologic agent in genetic skeletal disorders. 5) Assess the synthesis of bone G1a protein by calf bone organ cultures and isolated calf bone cells and compare to the synthesis of bone collagen, and other noncollagenous proteins. 6) Investigatate the mechanism of degradation of bone G1a protein in an in vitro calf bone culture system. 7) Search for a second unique Gamma-carboxyglutamic acid containing protein of bone. These experiments are designed to provide insight into the biological function of one specific vitamin K dependent protein, as well as to understand the spectrum of effects of vitamin K on bone metabolism and physiology. The focussed understanding of the relationship of a bone protein to underlying bone metabolism may provide valuable biochemical insight for the management of problems such as osteoporosis, non-union fractures, and metabolic bone diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR035056-02
Application #
3157018
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1984-12-01
Project End
1987-11-30
Budget Start
1985-12-01
Budget End
1986-11-30
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Southern California
Department
Type
Schools of Medicine
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90033
Zhao, J; Nishimoto, S K (1996) Matrix Gla protein gene expression is elevated during postnatal development. Matrix Biol 15:131-40
Zhao, J; Araki, N; Nishimoto, S K (1995) Quantitation of matrix Gla protein mRNA by competitive polymerase chain reaction using glyceraldehyde-3-phosphate dehydrogenase as an internal control. Gene 155:159-65
Zhao, J; Nishimoto, S K (1995) An RNA-competitive polymerase chain reaction method for human matrix gamma-carboxyglutamic acid protein mRNA measurement. Anal Biochem 228:162-4
Nishimoto, S K; Zhao, J; Dass, C (1994) Isolation and characterization of the reaction product of 4-diazobenzenesulfonic acid and gamma-carboxyglutamic acid: modification of the assay for measurement of beta-carboxyaspartic acid. Anal Biochem 216:159-64
Nishimoto, S K; Robinson, F D; Snyder, D L (1993) Effect of aging and dietary restriction on matrix Gla protein and other components of rat tracheal cartilage. Matrix 13:373-80
Nishimoto, S K; Araki, N; Robinson, F D et al. (1992) Discovery of bone gamma-carboxyglutamic acid protein in mineralized scales. The abundance and structure of Lepomis macrochirus bone gamma-carboxyglutamic acid protein. J Biol Chem 267:11600-5
Nishimoto, S K (1990) A colorimetric assay specific for gamma-carboxyglutamic acid-containing proteins: its utility in protein purification procedures. Anal Biochem 186:273-9
Nishimoto, S K; Padilla, S M; Snyder, D L (1990) The effect of food restriction and germ-free environment on age-related changes in bone matrix. J Gerontol 45:B164-8