Specific subcellular targeting of PKCalpha and PKCepsilon in normal and tumoral lactotroph cells by PMA-mitogenic stimulus.
The variations of the intracellular localization of the individual protein kinase C (PKC) isoforms are related with their different biological functions. In this study, we have investigated the precise intracellular translocation of endogenous PKCalpha and PKCepsilon in PMA-stimulated normal and tumoral lactotroph cells by using confocal and immunogold electron microscopy, which was correlated with the rate of cell proliferation of both pituitary cell phenotypes. The present results showed that the short phorbol ester incubation stimulated the proliferation of normal and tumoral lactotroph cells, as determined by the measurement of the BrdU-labelling index. The translocation of PKCalpha to plasma and nuclear membranes induced by PMA was more marked than that observed for PKCepsilon in normal and tumoral lactotroph cells. Our results showed that PKCs translocation to the plasma and nuclear membranes varied from isozyme to isozyme emphasizing that PKCalpha could be related with the mitogenic stimulus exerted by phorbol ester. These data support the notion that specific PKC isozymes may exert spatially defined effects by virtue of their directed translocation to distinct intracellular sites.
Petiti
Juan Pablo
JP
Centro de Microscopía Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Haya de la Torre Esq. Enrique Barros, 5000 Cordoba, Argentina. jpetiti@cmefcm.uncor.edu
Gutiérrez
Silvina
S
Mukdsi
Jorge Humberto
JH
De Paul
Ana Lucía
AL
Torres
Alicia Inés
AI
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D005455:Fluorescent Antibody Technique; D052682:Lactotrophs / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology* / Q000648:ultrastructure; D008934:Mitogens / Q000494:pharmacology; D009685:Nuclear Envelope / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D010911:Pituitary Neoplasms / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D051571:Protein Kinase C-alpha / Q000378:metabolism* / Q000648:ultrastructure; D051744:Protein Kinase C-epsilon / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D008934:Mitogens; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D013755:Tetradecanoylphorbol Acetate