title: Evidence that PC2 is the endogenous pro-neurotensin convertase in rMTC 6-23 cells and that PC1- and PC2-transfected PC12 cells differentially process pro-neurotensin.
abstract: The neuropeptide precursor proneurotensin/neuromedin N (pro-NT/NN) is mainly expressed and differentially processed in the brain and in the small intestine. We showed previously that rMTC 6-23 cells process pro-NT/NN with a pattern similar to brain tissue and increase pro-NT/NN expression in response to dexamethasone, and that PC12 cells also produce pro-NT/NN but are virtually unable to process it. In addition, PC12 cells were reported to be devoid of the prohormone convertases PC1 and PC2. The present study was designed to identify the proprotein convertase(s) (PC) involved in pro-NT/NN processing in rMTC 6-23 cells and to compare PC1- and PC2-transfected PC12 cells for their ability to process pro-NT/NN. rMTC 6-23 cells were devoid of PC1, PC4, and PC5 but expressed furin and PC2. Stable expression of antisense PC2 RNA in rMTC 6-23 cells led to a 90% decrease in PC2 protein levels that correlated with a > 80% reduction of pro-NT/NN processing. PC2 expression was stimulated by dexamethasone in a time- and concentration-dependent manner. Stable PC12/PC2 transfectants processed pro-NT/NN with a pattern similar to that observed in the brain and in rMTC 6-23 cells. In contrast, stable PC12/PC1 transfectants reproduced the pro-NT/NN processing pattern seen in the gut. We conclude that (i) PC2 is the major pro-NT/NN convertase in rMTC 6-23 cells; (ii) its expression is coregulated with that of pro-NT/NN in this cell line; and (iii) PC2 and PC1 differentially process pro-NT/NN with brain and intestinal phenotype, respectively.
authors.affiliation: Institut de Pharmacologie Moléculaire et Cellulaire du CNRS, Université de Nice-Sophia Antipolis, Valbonne, France.
authors.forename: C
authors.initials: C
authors.lastname: Rovère
authors.forename: P
authors.initials: P
authors.lastname: Barbero
authors.forename: P
authors.initials: P
authors.lastname: Kitabgi
mesh_terms: D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D002460:Cell Line; D017931:DNA Primers; D016373:DNA, Antisense; D003907:Dexamethasone / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism; D009496:Neurotensin / Q000378:metabolism*; D016716:PC12 Cells; D016133:Polymerase Chain Reaction; D045706:Proprotein Convertase 2; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D013381:Subtilisins / Q000096:biosynthesis / Q000378:metabolism*; D013964:Thyroid Neoplasms; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D016373:DNA, Antisense; D009363:Neoplasm Proteins; D011498:Protein Precursors; D012333:RNA, Messenger; D011994:Recombinant Proteins; C052457:neuromedin N precursor; D009496:Neurotensin; D003907:Dexamethasone; D013381:Subtilisins; D045706:Proprotein Convertase 2