Carboxypeptidase E is a regulated secretory pathway sorting receptor: genetic obliteration leads to endocrine disorders in Cpe(fat) mice.
A proposed mechanism for sorting secretory proteins into granules for release via the regulated secretory pathway in endocrine-neuroendocrine cells involves binding the proteins to a sorting receptor at the trans-Golgi network, followed by budding and granule formation. We have identified such a sorting receptor as membrane-associated carboxypeptidase E (CPE) in pituitary Golgi-enriched and secretory granule membranes. CPE specifically bound regulated secretory pathway proteins, including prohormones, but not constitutively secreted proteins. We show that in the Cpe(fat) mutant mouse lacking CPE, the pituitary prohormone, pro-opiomelanocortin, was missorted to the constitutive pathway and secreted in an unregulated manner. Thus, obliteration of CPE, the sorting receptor, leads to multiple endocrine disorders in these genetically defective mice, including hyperproinsulinemia and infertility.
Cool
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DR
Section on Cellular Neurobiology, Laboratory of Developmental Neurobiology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Normant
E
E
Shen
F
F
Chen
H C
HC
Pannell
L
L
Zhang
Y
Y
Loh
Y P
YP
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D043423:Carboxypeptidase H; D002268:Carboxypeptidases / Q000378:metabolism / Q000502:physiology*; D002417:Cattle; D002460:Cell Line; D053379:Chromogranin A; D002864:Chromogranins / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000201:enzymology*; D004298:Dopamine / Q000494:pharmacology; D004700:Endocrine System Diseases / Q000201:enzymology*; D005260:Female; D006056:Golgi Apparatus / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000201:enzymology* / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D009490:Neurosecretory Systems / Q000166:cytology; D010902:Pituitary Gland / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D021382:Protein Sorting Signals; D011506:Proteins / Q000378:metabolism*; D016372:RNA, Antisense
D053379:Chromogranin A; D002864:Chromogranins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D011506:Proteins; D016372:RNA, Antisense; D011333:Pro-Opiomelanocortin; D002268:Carboxypeptidases; D043423:Carboxypeptidase H; D004298:Dopamine