A distal nephron glycoprotein that has different cell surface distributions on MDCK cell sublines.
Monoclonal antibodies that recognize three distinct epitopes of a 23-kDa glycoprotein (gp23) on the plasma membrane of MDCK cells were used to study cell-surface polarity. Immunofluorescence microscopy of MDCK cells obtained from the American Type Culture Collection demonstrated that gp23 was nonpolarized in approximately 50% of the cells (on both apical and basolateral membranes), whereas, in the remaining cells, gp23 had a polarized distribution (basolateral only). This heterogeneous gp23 cell-surface staining was not observed in a variety of other MDCK sublines. Instead, gp23 was found to have a nonpolarized distribution on MDCK cells that produced monolayers with low transepithelial electrical resistances (less than 220 omega X cm2) and was localized only to the basolateral membrane of MDCK cell lines capable of generating considerably higher transepithelial electrical resistances (770-2,220 omega X cm2). Immunofluorescence and immunoelectron microscopy of dog, rat, and rabbit kidney demonstrated that gp23 is a nephron segment-specific glycoprotein localized only to the distal and collecting tubules. These observations provide further evidence for the heterogeneity of the MDCK cell line. They also support a proposal that the origin of MDCK cells is the renal distal nephron.
Ojakian
G K
GK
Romain
R E
RE
Herz
R E
RE
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D007158:Immunologic Techniques; D007668:Kidney / Q000378:metabolism; D008322:Mammals / Q000378:metabolism; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009399:Nephrons / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure
D006023:Glycoproteins