Identification of a specific binding protein for 1alpha,25-dihydroxyvitamin D3 in basal-lateral membranes of chick intestinal epithelium and relationship to transcaltachia

The steroid hormone 1 alpha,25-dihydroxyvitamin D3 1 alpha,25-(OH)2D3) elicits biological responses by both genomic and nongenomic pathways. This report describes purification of a receptor for 1 alpha,25-(OH)2D3 (VDR) located in the basal-lateral membrane (BLM) of vitamin D-replete chick intestinal...

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Bibliographic Details
Published in:The Journal of biological chemistry 1994, Vol.269
Main Authors: Nemere I, Dormanen M.C, Hammond M.W, Okamura W.H, Norman A.W
Format: Article
Language:English
Subjects:
binding proteins
chemoreceptors
chicks
chimiorecepteur
esteroles
intestin
intestines
intestinos
membrana mucosa
mucous membrane
muqueuse
pollito
poussin
proteinas aglutinantes
proteine de liaison
purificacion
purification
quimioreceptores
sterol
sterols
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Summary:The steroid hormone 1 alpha,25-dihydroxyvitamin D3 1 alpha,25-(OH)2D3) elicits biological responses by both genomic and nongenomic pathways. This report describes purification of a receptor for 1 alpha,25-(OH)2D3 (VDR) located in the basal-lateral membrane (BLM) of vitamin D-replete chick intestinal epithelium, which is implicated in the nongenomic stimulation of calcium transport (transcaltachia). The BLM-VDR exhibited saturable binding for [3H]1,25-(OH)2D3 (KD = 0.72 X 10(-9) M, Bmax = 0.24 pmol/mg of protein). A 4500-fold purification of the BLM-VDR receptor was achieved. In addition, saturable binding was observed for [3H]24R,25-(OH)2D3 at physiologically relevant levels (KD = 19 X 10(-9) M, Bmax, = 2.4 pmol/mg of protein) to a component apparently distinct from the 1 alpha,25-(OH)2D3 BLM-VDR. A functional correlation between the BLM-VDR and transcaltachia was observed in three experimental situations: (i) vitamin D deficiency, which suppresses transcaltachia, resulted in reduced specific [3H] 1 alpha,25(OH)2D3 binding in the BLM-VDR, relative to corresponding fractions from vitamin D-replete chicks; (ii) the BLM-VDR exhibited down-regulation of specific [3H]1 alpha,25-(OH)2D3 binding following exposure to nonradioactive 1 alpha,25-(OH)2D3; and (iii) the relative potencies of two "6-s-cis" analogs of 1 alpha,25-(OH)2D3 to initiate transcaltachia and their ability to compete with [3H]1 alpha,25(OH)2D3 for binding to the BLM-VDR were parallel. The combined results support the existence of a plasmalemmal 1 alpha-25,(OH)-2D3 receptor which is a prime candidate for signal transduction in transcaltachia.
ISSN:0021-9258
1083-351X