The neuroendocrine chaperone 7B2 can enhance in vitro POMC cleavage by prohormone convertase PC2.
We previously showed that the neuroendocrine polypeptide 7B2 transiently interacts with prohormone convertase PC2 in the secretory pathway of neuroendocrine cells. Here we demonstrate that the processed, but not the intact, form of 7B2 can enhance the in vitro cleavage of newly synthesized prohormone proopiomelanocortin (POMC) in lysates of Xenopus intermediate pituitary cells. PC2 is presumably the cleavage enzyme involved since intact 7B2 abolishes the enhancing effect of processed 7B2 and is known to act as a specific inhibitor of PC2. Furthermore, processed 7B2 stimulates in vitro POMC cleavage by immunopurified Xenopus PC2. Our results indicate that 7B2 can display chaperone activity towards PC2.
Braks
J A
JA
Department of Animal Physiology, University of Nijmegen, The Netherlands.
Martens
G J
GJ
D000818:Animals; D004492:Edetic Acid / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008970:Molecular Weight; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D051859:Neuroendocrine Secretory Protein 7B2; D010902:Pituitary Gland / Q000378:metabolism; D010907:Pituitary Hormones / Q000494:pharmacology*; D011333:Pro-Opiomelanocortin / Q000378:metabolism*; D045706:Proprotein Convertase 2; D011994:Recombinant Proteins / Q000494:pharmacology; D013381:Subtilisins / Q000302:isolation & purification / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D014982:Xenopus laevis
D009419:Nerve Tissue Proteins; D051859:Neuroendocrine Secretory Protein 7B2; D010907:Pituitary Hormones; D011994:Recombinant Proteins; D013462:Sulfur Radioisotopes; D011333:Pro-Opiomelanocortin; D004492:Edetic Acid; D013381:Subtilisins; D045706:Proprotein Convertase 2