tailieunhanh - Báo cáo khoa học: Differential involvement of protein kinase C alpha and epsilon in the regulated secretion of soluble amyloid precursor protein

We investigated the differential role of protein kinase C (PKC) isoforms in the regulated proteolytic release of soluble amyloid precursor protein (sAPPa)inSH-SY5Y neuroblastoma cells. We used cells stably transfected with cDNAs encoding either PKCaor PKCein the antisense orientation, producing a reduction of the expression of PKCa and PKCe, respectively. Reduced expression of PKCaand/or PKCedid not modify the response of the kinase to phorbol ester stimulation, demonstrating translo. | Eur. J. Biochem. 271 3068-3075 2004 FEBS 2004 doi Differential involvement of protein kinase C alpha and epsilon in the regulated secretion of soluble amyloid precursor protein Cristina Lanni Michela Mazzucchelli Emanuela Porrello Stefano Govoni and Marco Racchi Department of Experimental and Applied Pharmacology Centre of Excellence in Applied Biology and School of Pharmacy University of Pavia Viale Taramelli 14 27100 Pavia Italy We investigated the differential role of protein kinase C PKC isoforms in the regulated proteolytic release of soluble amyloid precursor protein sAPPa in SH-SY5Y neuroblastoma cells. We used cells stably transfected with cDNAs encoding either PKCa or PKCe in the antisense orientation producing a reduction of the expression of PKCa and PKCe respectively. Reduced expression of PKCa and or PKCe did not modify the response of the kinase to phorbol ester stimulation demonstrating translocation of the respective isoforms from the cytosolic fraction to specific intracellular compartments with an interesting differential localization of PKCa to the plasma membrane and PKCe to Golgi-like structures. Reduced expression of PKCa significantly impaired the secretion of sAPPa induced by treatment with phorbol esters. Treatment of PKCa-deficient cells with carbachol induced a significant release of sAPPa. These results suggest that the involvement of PKCa in carbachol-induced sAPPa release is negligible. The response to carbachol is instead completely blocked in PKCe-deficient cells suggesting the importance of PKCe in coupling cholinergic receptors with APP metabolism. Keywords Alzheimer s disease cholinergic receptors neuroblastoma phorbol esters signal transduction. Alzheimer s disease AD the most common type of dementia is characterized by deposition in the brain of fibrillar aggregates of a peptide named beta-amyloid Ab derived from proteolytic processing of a larger precursor called amyloid precursor protein APP 1