Osteocalcin

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Bone gamma-carboxyglutamate (gla) protein
Osteocalcin 1Q8H.png
PDB rendering based on 1q8h.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols BGLAP ; BGP; OC; OCN
External IDs OMIM112260 MGI88156 HomoloGene104130 GeneCards: BGLAP Gene
Orthologs
Species Human Mouse
Entrez 632 12095
Ensembl ENSG00000242252 ENSMUSG00000074489
UniProt P02818 P54615
RefSeq (mRNA) NM_199173 NM_031368.4
RefSeq (protein) NP_954642 NP_112736.3
Location (UCSC) Chr 1:
156.21 – 156.21 Mb
Chr 3:
88.37 – 88.37 Mb
PubMed search [1] [2]
Not to be confused with Osteonectin or Osteopontin.

Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein (BGLAP), is a noncollagenous protein found in bone and dentin. Because it has gla domains, its synthesis is vitamin K dependent. In humans, the osteocalcin is encoded by the BGLAP gene.[1][2] Its receptor is GPRC6A.[3]

Function[edit]

Osteocalcin is secreted solely by osteoblasts and thought to play a role in the body's metabolic regulation and is pro-osteoblastic, or bone-building, by nature.[4] It is also implicated in bone mineralization and calcium ion homeostasis. Osteocalcin acts as a hormone in the body, causing beta cells in the pancreas to release more insulin, and at the same time directing fat cells to release the hormone adiponectin, which increases sensitivity to insulin.[4]

Current data suggests a possible role of osteocalcin in male fertility.[5] Research from Columbia University Medical Center proposes that osteocalcin may enhance the synthesis of testosterone.[6] Although these studies were initially performed by only a single laboratory, at least two other groups have independently confirmed the role of osteocalcin in insulin secretion.[7][8]

Use as a biochemical marker for bone formation[edit]

As osteocalcin is produced by osteoblasts, it is often used as a marker for the bone formation process. It has been observed that higher serum-osteocalcin levels are relatively well correlated with increases in bone mineral density (BMD) during treatment with anabolic bone formation drugs for osteoporosis, such as Teriparatide. In many studies, osteocalcin is used as a preliminary biomarker on the effectiveness of a given drug on bone formation. For instance, one study which aimed to study the effectiveness of a glycoprotein called lactoferrin on bone formation used osteocalcin as a measure of osteoblast activity.[9]

References[edit]

  1. ^ Puchacz E, Lian JB, Stein GS, Wozney J, Huebner K, Croce C (May 1989). "Chromosomal localization of the human osteocalcin gene". Endocrinology 124 (5): 2648–50. doi:10.1210/endo-124-5-2648. PMID 2785029. 
  2. ^ Cancela L, Hsieh CL, Francke U, Price PA (September 1990). "Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene". J. Biol. Chem. 265 (25): 15040–8. PMID 2394711. 
  3. ^ http://www.ncbi.nlm.nih.gov/pubmed/21425331
  4. ^ a b Lee NK, Sowa H, Hinoi E, Ferron M, Ahn JD, Confavreux C, Dacquin R, Mee PJ, McKee MD, Jung DY, Zhang Z, Kim JK, Mauvais-Jarvis F, Ducy P, Karsenty G (August 2007). "Endocrine regulation of energy metabolism by the skeleton". Cell 130 (3): 456–69. doi:10.1016/j.cell.2007.05.047. PMC 2013746. PMID 17693256. 
  5. ^ Franck Oury, Grzegorz Sumara, Olga Sumara, Mathieu Ferron, Haixin Chang, Charles E. Smith, Louis Hermo, Susan Suarez, Bryan L. Roth, Patricia Ducy et al. Endocrine Regulation of Male Fertility by the Skeleton. Cell, 17 February 2011 doi:10.1016/j.cell.2011.02.004
  6. ^ Testosterone
  7. ^ Pi M, Wu Y, Quarles DL (July 2011). "GPRC6A mediates responses to osteocalcin in beta-cells in vitro and pancreas in vivo". JBMR 26 (7): 1680–1683. doi:10.1002/jbmr.390. PMID 21425331. 
  8. ^ Fulzele K, Riddle RC, DiGirolamo DJ, Cao X, Wan C, Chen D, Faugere MC, Aja S, Hussain MA, Brüning JC, Clemens TL (July 2010). "Insulin receptor signaling in osteoblasts regulates postnatal bone acquisition and body composition". Cell 142 (2): 309–19. doi:10.1016/j.cell.2010.06.002. PMC 2925155. PMID 20655471. 
  9. ^ Bharadwaj S, Naidu AG, Betageri GV, Prasadarao NV, Naidu AS (September 2009). "Milk ribonuclease-enriched lactoferrin induces positive effects on bone turnover markers in postmenopausal women". Osteoporos Int 20 (9): 1603–11. doi:10.1007/s00198-009-0839-8. PMID 19172341. 

Further reading[edit]

External links[edit]