Identification of a sorting signal for the regulated secretory pathway at the N-terminus of pro-opiomelanocortin.
The N-terminal 26 amino acids of the prohormone pro-opiomelanocortin (POMC) were investigated to determine whether this region has the capacity to act as a sorting signal for the regulated secretory pathway. Constructs were made using the N-terminal 101, 50, 26 or 10 amino acids of POMC fused to the chloramphenicol acetyltransferase (CAT) reporter protein and expressed in AtT20 cells to show that at least the first 26 amino acids were required to sort CAT to the regulated secretory pathway. Full length POMC was mutated by deleting amino acids 2-26 from the N-terminal region. Analysis of Neuro-2a cells expressing this mutation compared to wild type POMC indicated that these 26 amino acids contain information essential for sorting POMC to the regulated secretory pathway. The results presented here suggest the presence of a conformation-dependent signal in the N-terminal 26 amino acids of POMC responsible for sorting POMC to the regulated secretory pathway.
Cool
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DR
Section on Cellular Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
Loh
Y P
YP
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D011333:Pro-Opiomelanocortin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D011333:Pro-Opiomelanocortin; D015500:Chloramphenicol O-Acetyltransferase