Genomic mechanisms involved in the pleiotropic actions of 1,25-dihydroxyvitamin D3

摘要: The biologically active metabolite of vitamin D (cholecalciferol), i.e. 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], is a secosteroid hormone whose mode action involves stereospecific interaction with an intracellular receptor protein (vitamin receptor; VDR). 1,25(OH)2D3 known to be principal regulator calcium homeostasis, and it has numerous other physiological functions including inhibition proliferation cancer cells, effects on secretion suppression T-cell cytokine production. Although the exact mechanisms involved in mediating many different are not completely defined, genomic actions involving VDR clearly major importance. Similar steroid receptors, phosphorylated; however, functional role phosphorylation remains determined. been reported regulated by also activation kinases A C, suggesting co-operativity between signal transduction pathways action. binds D-responsive elements (VDREs) 5´ flanking region target genes. It suggested that homodimerization can occur upon binding certain VDREs but VDR/retinoid X (RXR) heterodimer transactivating species. Other factors VDR-mediated transcription include chicken ovalbumin upstream promoter (COUP) factor, which silencing transcription, factor IIB, play following VDR/RXR heterodimerization. Newly identified D-dependent genes those for Ca2+/Mg2+-ATPase intestine p21 myelomonocytic U937 cell line. Elucidation multiple will area future research.