1,25-Dihydroxyvitamin D3 selectively induces increased expression of the Na,K-ATPase beta 1 subunit in avian myelomonocytic cells without a concomitant change in Na,K-ATPase activity.
Treatment of avian myelomonocytic cells with 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) results in an approximately two fold increase in levels of Na,K-ATPase beta 1 subunit mRNA and protein (both total and plasma membrane-associated). The changes in beta 1 subunit expression occur in the absence of a detectable increase in expression of any of the three alpha subunit isoforms or in Na,K-ATPase activity. The selective induction of the expression of the beta subunit in avian myelomonocytic cells by 1,25(OH)2D3 reveals a previously unobserved feature of the regulation of Na,K-ATPase expression, while the targeting of beta subunit polypeptides to the plasma membrane in the absence of a corresponding increase in active Na,K-ATPase suggests that, in these cells, transport of the beta subunit to the plasma membrane may be independent of its binding to the alpha subunit.
Billecocq
A
A
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8044, USA.
Horne
W C
WC
Chakraborty
M
M
Takeyasu
K
K
Levenson
R
R
Baron
R
R
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects* / Q000201:enzymology*; D001854:Bone Marrow Cells; D002117:Calcitriol / Q000494:pharmacology*; D002462:Cell Membrane / Q000201:enzymology; D002645:Chickens / Q000378:metabolism*; D004790:Enzyme Induction; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007527:Isoenzymes; D000254:Sodium-Potassium-Exchanging ATPase; D002117:Calcitriol