A novel type of cell-cell cooperation between epithelial cells.
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 beta-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.
Contreras
R G
RG
Center for Research & Advanced Studies, México, D.F., México.
Lázaro
A
A
Bolivar
J J
JJ
Flores-Maldonado
C
C
Sánchez
S H
SH
González-Mariscal
L
L
García-Villegas
M R
MR
Valdés
J
J
Cereijido
M
M
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004285:Dogs; D004351:Drug Resistance; D004847:Epithelial Cells; D007668:Kidney; D008253:Macaca mulatta; D010042:Ouabain / Q000378:metabolism / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects / Q000378:metabolism
D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium