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[Molecular mechanisms of vitamin K action in the bone homeostasis]
Tomoe Ichikawa1, Satoshi Inoue
1Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical School.
Abstract:
Vitamin K is used as an anti-osteoporosis drug in Japan. Moreover, vitamin K intake has been found to decrease hip fracture risk. In the bone homeostasis, vitamin K action is mediated through two molecular mechanisms: posttranslational modification of proteins, and regulation of gene expression. The former is vitamin K-dependent carboxylation, in which vitamin K functions as an essential cofactor for modification of glutamic acid residues to gamma-carboxyglutamic acid residues. The latter is a novel mechanism that regulates the transcription of target genes by vitamin K through activation of steroid and xenobiotic receptor (SXR). The two mechanisms may coordinately contribute to vitamin K function in the bone metabolism.
Insights
Vitamin K plays a crucial role in bone health by aiding in protein modification and regulating gene expression, potentially reducing osteoporosis and hip fracture risks.
Area of Science:
- Biochemistry
- Molecular Biology
- Bone Metabolism
Context:
- Vitamin K is utilized as an anti-osteoporosis medication in Japan.
- Vitamin K intake is associated with a reduced risk of hip fractures.
- Bone homeostasis involves complex molecular mechanisms.
Purpose:
- To elucidate the molecular mechanisms of vitamin K action in bone metabolism.
- To investigate the role of vitamin K in protein modification and gene expression related to bone health.
Summary:
- Vitamin K acts as an essential cofactor in vitamin K-dependent carboxylation, modifying glutamic acid residues to gamma-carboxyglutamic acid residues.
- Vitamin K regulates gene transcription via the steroid and xenobiotic receptor (SXR), a newly identified mechanism.
- These two pathways, protein carboxylation and gene regulation, likely work together to influence bone metabolism.
Impact:
- Provides insight into the dual mechanisms of vitamin K in bone health.
- Highlights potential therapeutic targets for osteoporosis and fracture prevention.
- Contributes to understanding the broader role of vitamin K beyond coagulation.
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