Yeast KEX1 protease cleaves a prohormone processing intermediate in mammalian cells.
A vaccinia virus vector was used to express the yeast KEX1 gene, which encodes a prohormone carboxypeptidase specific for the removal of basic amino acids from prohormone processing intermediates, in mammalian cells. When produced in BSC-40 cells, Kex1p was localized to the perinuclear region and conferred a large increase in enzymatic activity characteristic of this carboxypeptidase. Expression of the KEX1 gene together with the yeast KEX2 gene, which encodes a prohormone endopeptidase specific for cleavage at pairs of basic amino acids, and the mouse proopiomelanocortin (mPOMC) cDNA in BSC-40 cells resulted in the full conversion of mPOMC to mature peptides including gamma-lipotropin. This in vivo processing of mPOMC to mature peptides by the KEX2/KEX1 gene products demonstrates a significant functional homology of the basic prohormone processing machinery in yeast and neuroendocrine cells.
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201-3098.
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D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D005822:Genetic Vectors; D051379:Mice; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism*; D043484:Proprotein Convertases; D011498:Protein Precursors / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D013381:Subtilisins; D014162:Transfection; D014616:Vaccinia virus / Q000235:genetics; D008083:beta-Lipotropin / Q000378:metabolism
D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; D011333:Pro-Opiomelanocortin; D008083:beta-Lipotropin; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae