Activation and protein kinase C-dependent nuclear accumulation of ERK in differentiating human neuroblastoma cells.
The human neuroblastoma cell line SH-SY5Y is a well characterized model for sympathetic neuronal differentiation in vitro. Several differentiation protocols exist, one of which, the addition of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) in the presence of serum, has been thoroughly studied. Wild-type SH-SY5Y cells are unresponsive to nerve growth factor (NGF), but cells transfected with the high-affinity NGF receptor TrkA (SH-SY5Y/TrkA) differentiate in response to NGF. In the present study, we have addressed the existence of a differentiation-specific mode of activation and subcellular distribution of the extracellular signal-regulated kinases ERK1 and ERK2 in SH-SY5Y/wt and SH-SY5Y/TrkA. Both TPA and NGF induced a sustained activation and nuclear accumulation of ERK that was accompanied by transactivation of a serum response element (SRE)-driven reporter and of the c-fos gene. However, activation and nuclear accumulation of ERK were not sufficient to induce neuronal differentiation in SH-SY5Y, as demonstrated by the response to TPA in serum-free cultures. Nuclear accumulation but not activation of ERK was demonstrated to require active protein kinase C (PKC). The effect of specific PKC inhibitors on subcellular distribution of ERK and ERK-dependent transcription suggests a functional role for PKC in the regulation of nuclear ERK activity in SH-SY5Y neuroblastoma cells.
Olsson
A K
AK
Department of Genetics and Pathology, The Rubeck Laboratory, Uppsala, S-751 85, Sweden.
Vadhammar
K
K
Nånberg
E
E
D000077214:Becaplermin; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000201:enzymology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020932:Nerve Growth Factor / Q000494:pharmacology; D009447:Neuroblastoma; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011233:Precipitin Tests; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis; D013347:Subcellular Fractions / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D020932:Nerve Growth Factor; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate