ISSN:
1432-1424
Keywords:
Ouabain-resistance
;
Epithelia
;
Ma104 cells
;
MDCK cells
;
Tight junctions
;
Na+, K+-ATPase
;
K+ content
;
Metabolic cooperation
;
Cell attachment
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Ma104 cells (renal, epithelial) have a peculiar way of resisting ouabain: their Na+,K+-pumps bind the drug with high affinity, cellular K+ is lost and cell division arrested, but cells do not detach as most cell types do. Then, if up to 4 days later the drug is removed, Ma104 cells recover K+ and resume proliferation (Contreras et al., 1994). In the present work, we investigate whether Ma104 cells are able to protect ouabain-sensitive MDCK cells in co-culture. The main finding is that they do, but in this case protection is not elicited by the usual mechanism of maintaining the K+ content of neighboring cells through cell-cell communications. Ma104 cells treated with ouabain simply remain attached to the substrate and to their MDCK neighbors, and both cells lose K+. This attachment includes tight junctions, because the transepithelial electrical resistance of the monolayers is not abolished by ouabain. Although the β-subunit of the Na+,K+-ATPase is known to possess molecular characteristics of cell-cell attachment molecules, attachment between Ma104-MDCK cells does not seem to be mediated by this enzyme, as immunofluorescence analysis reveals that Na+,K+-ATPase is only inserted in the plasma membrane facing a neighboring cell of the same type.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00232722
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