Abstract

The overall aim of this proposal is to further characterize the structure and properties of this novel osteoclast-specific proton pump (OC- H plus/minus ATPase), focusing mostly on the catalytic portion of the transporter and its 63kd subunit and on the unique vanadate sensitive component of this pump. Based upon our preliminary data, this proposal will address the following specific aims: (1) Clone and sequence, using classical and PCR methods, the two catalytic subunits of the OC- H+ATPase in order to determine the molecular basis for the unique nitrate and vanadate sensitivity of this proton pump; the selection of the catalytic subunits as our first targets is based upon the fact that vanadate is known to interact with the catalytic portion of ATPases; (2) Purify the OC- H+ATPase from chicken osteoclasts, in order to characterize the enzyme biochemically and identify the vanadate and nitrate sensitive components(s), and (3) Study the regulation of the expression and function of the OC- H+ATPase by calciotropic and sexual hormones. This program could lead to the development of new therapeutic approaches based upon the unique properties of the OC- H+ATPase and may in the long run allow the specific inhibition of acid secretion by the osteoclast, inhibiting bone resorption in diseases where it is increased (osteoporosis and others).

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR041339-02
Application #
3161732
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Project Start
1991-09-30
Project End
1994-08-31
Budget Start
1992-09-01
Budget End
1993-08-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost

  Institution

Name
Yale University
Department
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520

  Publications

Baron, R (1996) Molecular mechanisms of bone resorption: therapeutic implications. Rev Rhum Engl Ed 63:633-8
David, P; Horne, W C; Baron, R (1996) Vanadate inhibits vacuolar H(+)-ATPase-mediated proton transport in chicken kidney microsomes by an ADP-dependent mechanism. Biochim Biophys Acta 1280:155-60
David, P; Nguyen, H; Barbier, A et al. (1996) The bisphosphonate tiludronate is a potent inhibitor of the osteoclast vacuolar H(+)-ATPase. J Bone Miner Res 11:1498-507
Hernando, N; Bartkiewicz, M; Collin-Osdoby, P et al. (1995) Alternative splicing generates a second isoform of the catalytic A subunit of the vacuolar H(+)-ATPase. Proc Natl Acad Sci U S A 92:6087-91
Bartkiewicz, M; Hernando, N; Reddy, S V et al. (1995) Characterization of the osteoclast vacuolar H(+)-ATPase B-subunit. Gene 160:157-64
Ravesloot, J H; Eisen, T; Baron, R et al. (1995) Role of Na-H exchangers and vacuolar H+ pumps in intracellular pH regulation in neonatal rat osteoclasts. J Gen Physiol 105:177-208
Baron, R (1995) Molecular mechanisms of bone resorption. An update. Acta Orthop Scand Suppl 266:66-70
David, P; Baron, R (1994) The catalytic cycle of the vacuolar H(+)-ATPase. Comparison of proton transport in kidney- and osteoclast-derived vesicles. J Biol Chem 269:30158-63
Chatterjee, D; Neff, L; Chakraborty, M et al. (1993) Sensitivity to nitrate and other oxyanions further distinguishes the vanadate-sensitive osteoclast proton pump from other vacuolar H(+)-ATPases. Biochemistry 32:2808-12
Chatterjee, D; Chakraborty, M; Leit, M et al. (1992) The osteoclast proton pump differs in its pharmacology and catalytic subunits from other vacuolar H(+)-ATPases. J Exp Biol 172:193-204

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