HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Boning Up on Vitamin K2 Function

Vitamin K2 promotes collagen expression in osteoblastic cells.

Vitamin K₂ (2-methyl-3-hexaprenyl-1,4-naphthoquinone) is an essential nutrient that has many functions including a role in bone formation. Supplementation with the vitamin enhances the expression of bone markers, increases bone density in vivo, and is used clinically in the management of osteoporosis. Vitamin K₂ was originally thought to contribute to bone formation via a role as an essential cofactor for -carboxylation of bone matrix proteins. More recent evidence suggests that the vitamin also has a transcriptional regulatory role arising from an ability to bind to and activate the steroid and xenobiotic receptor SXR and induce expression of target genes.

To further explore the SXR-mediated vitamin K₂ signaling network, Ichikawa and colleagues used DNA microarrays to identify three genes with increased expression in osteoblastic cell lines treated with vitamin K₂ and the classic SXR ligand rifampicin. Transfection and siRNA experiments showed that one of the three responsive genes, tsukushi, contributed to enhanced collagen accumulation. These results suggest a new function for vitamin K₂ in bone formation as a transcriptional regulator of extracellular matrix-related genes involved in collagen assembly.

FOOTNOTES

See referenced article, J. Biol. Chem. 2006, 281, 16927-16934

[More Papers of the Week]