Key result
In PC12 cells, CAMKII-mediated phosphorylation of dystrophin Dp71d modulates its nuclear localization, which is favored by cell depolarization and CaMKII overexpression.
This study demonstrates that CaMKII-mediated phosphorylation of dystrophin Dp71d regulates its nuclear localization in PC12 cells.
Findings in PC12 cells warrant clinical caution; extends mechanistic understanding of Dp71d nuclear shuttling in neuronal models.
We have shown that the splicing isoform of Dp71 (Dp71d) localizes to the nucleus of PC12 cells, an established cell line derived from a rat pheochromocytoma; however, the mechanisms governing its nuclear localization are unknown. As protein phosphorylation modulates the nuclear import of proteins, and as Dp71d presents several potential sites for phosphorylation, we analyzed whether Dp71d is phosphorylated in PC12 cells and the role of phosphorylation on its nuclear localization. We demonstrated that Dp71d is phosphorylated under basal conditions at serine and threonine residues by endogenous protein kinases. Dp71d phosphorylation was activated by 2-O-tetradecanoyl phorbol 13-acetate (TPA), but this effect was blocked by EGTA. Supporting the role of intracellular calcium on Dp71d phosphorylation, we observed that the stimulation of calcium influx by cell depolarization increased Dp71d phosphorylation, and that the calcium-calmodulin inhibitor N-(6-aminohexyl)-1-naphthalenesulfonamide (W-7) blocked such induction. The blocking action of bisindolylmaleimide I (Bis I), a specific inhibitor for Ca2+/diacylglicerol-dependent protein kinase (PKC), on Dp71d phosphorylation suggested the participation of PKC in this event. In addition, transfection experiments with Ca2+/calmodulin-dependent protein kinase II (CaMKII) expression vectors as well as the use of KN-62, a CaMKII-specific inhibitor, demonstrated that CaMKII is also involved in Dp71d phosphorylation. Stimulation of Dp71d phosphorylation by cell depolarization and/or the overexpression of CaMKII favored the Dp71d nuclear accumulation. Overall, our results indicate that CAMKII-mediated Dp71d phosphorylation modulates its nuclear localization.
No takes yet. Share an insight, caveat, or question.
Calderilla‐Barbosa et al. (2006) studied PC12 cell line (rat pheochromocytoma). Cell depolarization and CaMKII overexpression vs. Basal conditions or specific inhibitors (W-7, Bis I, KN-62) was evaluated on Dp71d phosphorylation and nuclear localization. In PC12 cells, CAMKII-mediated phosphorylation of dystrophin Dp71d modulates its nuclear localization, which is favored by cell depolarization and CaMKII overexpression.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: