Evidence for interference of vitamin D with PTH/PTHrP receptor expression in opossum kidney cells

1998 ◽  
Vol 436 (2) ◽  
pp. 289-294 ◽  
Author(s):  
H. Wald ◽  
Michal Dranitzki-Elhalel ◽  
R. Backenroth ◽  
Mordecai M. Popovtzer
2005 ◽  
Vol 20 (6) ◽  
pp. 721-724 ◽  
Author(s):  
Douglas M. Silverstein ◽  
Adrian Spitzer ◽  
Mario Barac-Nieto

2002 ◽  
Vol 283 (5) ◽  
pp. F1066-F1074 ◽  
Author(s):  
Sandrine V. Pierre ◽  
Marie-Josée Duran ◽  
Deborah L. Carr ◽  
Thomas A. Pressley

Specific functions served by the various Na+-K+-ATPase α-isoforms are likely to originate in regions of structural divergence within their primary structures. The isoforms are nearly identical, with the exception of the NH2 terminus and a 10-residue region near the center of each molecule (isoform-specific region; ISR). Although the NH2 terminus has been clearly identified as a source of isoform functional diversity, other regions seem to be involved. We investigated whether the central ISR could also contribute to isoform variability. We constructed chimeric molecules in which the central ISRs of rat α1- and α2-isoforms were exchanged. After stable transfection into opossum kidney cells, the chimeras were characterized for two properties known to differ dramatically among the isoforms: their K+ deocclusion pattern and their response to PKC activation. Comparisons with rat full-length α1- and α2-isoforms expressed under the same conditions suggest an involvement of the central ISR in the response to PKC but not in K+ deocclusion.


1986 ◽  
Vol 251 (5) ◽  
pp. F858-F864 ◽  
Author(s):  
A. P. Teitelbaum ◽  
R. A. Nissenson ◽  
L. A. Zitzner ◽  
K. Simon

Guanyl nucleotide regulation of parathyroid hormone (PTH)-activated adenylate cyclase was studied in membrane preparations of cultured opossum kidney cells. Guanosine triphosphate (GTP) (100 microM) decreased PTH-stimulated activity by 70%. Pertussis toxin enhanced PTH stimulation in intact cells and membranes, completely blocked the inhibitory effect of GTP, and catalyzed the [32P]ADP-ribosylation of a 38,000-dalton protein migrating in the position of the alpha-subunit of the inhibitory GTP-regulatory protein Ni. Cholera toxin was used to identify the alpha-subunit of the stimulatory GTP-binding protein Ns, a 42,000-dalton protein. We tested the idea that Ni may be involved in mediating the reduced response of opossum kidney cells to PTH after pretreatment with the hormone (desensitization). GTP inhibited PTH-stimulated activity to approximately the same degree in membranes from PTH-pretreated cells and control cells whether or not the cells had also received pertussis toxin. We conclude that GTP inhibits PTH action in opossum kidney cells through Ni but that PTH-induced desensitization is not mediated by Ni.


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