Transformation-sensitive localization of alpha-protein kinase C at cell-cell contacts in rat renal proximal tubule epithelial cells.
Immunocytofluorescence studies were used to compare alpha-protein kinase C (PKC) localization in primary cultures of renal proximal tubule epithelial cells (RPTE) with E1A-immortalized and SV40-transformed derivatives. Both cytosolic and nuclear staining were apparent in all of the RPTE. In primary RPTE, Triton X-100-insoluble alpha-PKC was also apparent and was concentrated in cell junctions. Cell junction alpha-PKC was diminished in E1A-immortalized and absent from SV40-transformed RPTE, even though total cellular content was not decreased. These results emphasize that subcellular location may play an important role in regulating signal transduction through PKC-dependent pathways. Phorbol ester treatment induced cell membrane ruffling in primary RPTE, and alpha-PKC was redistributed to membrane ruffles. However, the redistributed alpha-PKC was Triton soluble and, therefore, was distinct from cell junction alpha-PKC. The loss of alpha-PKC from cell junctions in phorbol ester-treated and oncogene-altered cells suggests that there are cellular determinants regulating alpha-PKC association with junctional complexes.
Dong
L
L
W. Alton Jones Cell Science Center, Inc., Lake Placid, New York 12946-1099.
Stevens
J L
JL
Jaken
S
S
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002472:Cell Transformation, Viral / Q000502:physiology; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D007527:Isoenzymes / Q000032:analysis*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000201:enzymology*; D008297:Male; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000032:analysis*; D051381:Rats; D011916:Rats, Inbred F344; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology
D007527:Isoenzymes; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C