Peptide biosynthetic processing: distinguishing prohormone convertases PC1 and PC2.
To determine whether manipulation of time, temperature and intragranular pH could be used to distinguish the actions of two subtilisin-related endoproteases, PC1 and PC2, in peptide biosynthesis, the biosynthetic processing of proneuropeptide Y (proNPY) and proopiomelanocortin (POMC) was examined in pituitary cell lines. AtT-20 cells express PC1 and POMC endogenously; stably transfected AtT-20 lines expressing NPY or PC2 were studied. GH3 cells express PC2 endogenously; NPY-expressing GH3 transfectants were investigated. PC1 mediated rapid processing of NPY and POMC; PC1-dependent cleavages were relatively insensitive to 20 degrees C blockade (which arrests secretory pathway transport at the trans-Golgi network) and do not require an acidic intracellular compartment (as in secretory granules). PC2 mediated much slower processing of proNPY and POMC which was totally blocked at 20 degrees C and required an acidic intracellular compartment. Thus, kinetics, abolition of intracellular pH gradients, and incubation at reduced temperatures can be used to distinguish PC1 and PC2 actions in neuroendocrine cells.
Paquet
L
L
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA.
Zhou
A
A
Chang
E Y
EY
Mains
R E
RE
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D002460:Cell Line; D006863:Hydrogen-Ion Concentration; D051379:Mice; D009478:Neuropeptide Y / Q000096:biosynthesis*; D010902:Pituitary Gland / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis*; D045664:Proprotein Convertase 1; D045706:Proprotein Convertase 2; D043484:Proprotein Convertases; D011498:Protein Precursors / Q000096:biosynthesis*; D051381:Rats; D013381:Subtilisins / Q000378:metabolism*; D013696:Temperature
D009478:Neuropeptide Y; D011498:Protein Precursors; C081158:proneuropeptide Y; D011333:Pro-Opiomelanocortin; D043484:Proprotein Convertases; D013381:Subtilisins; C473656:Pcsk1 protein, mouse; D045664:Proprotein Convertase 1; D045706:Proprotein Convertase 2; D016282:Aspartic Acid Endopeptidases