title: Secretion of egg envelope protein ZPC after C-terminal proteolytic processing in quail granulosa cells.
abstract: In avian species, an egg envelope homologous to the mammalian zona pellucida is called the perivitelline membrane. We have previously reported that one of its components, a glycoprotein homologous to mammalian ZPC, is synthesized in the granulosa cells of the quail ovary. In the present study, we investigated the proteolytic cleavage of the newly synthesized ZPC and the secretion of ZPC from the granulosa cells. Western blot analysis of the cell lysates demonstrated that the 43-kDa protein is the precursor of mature ZPC (proZPC), and is converted to the 35-kDa protein before secretion. The accumulation of proZPC in the presence of brefeldin A, and conversion of proZPC to ZPC in the presence of monensin, indicate the possibility that the proteolytic processing of ZPC occurs in the Golgi apparatus. An analysis of amino-acid sequence identified that the C terminus of mature ZPC protein is Phe360, and the N-terminal amino-acid sequence of the proZPC-derived fragment was determined as Asp363. These results suggest that newly synthesized ZPC is cleaved at the consensus furin cleavage site, and the resulting two basic residues at the C terminus are subsequently trimmed off to generate mature ZPC prior to secretion.
authors: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Japan.
authors: Tomohiro
authors: T
authors: Sasanami
authors: Jianzhi
authors: J
authors: Pan
authors: Yukio
authors: Y
authors: Doi
authors: Miki
authors: M
authors: Hisada
authors: Tetsuya
authors: T
authors: Kohsaka
authors: Masaru
authors: M
authors: Toriyama
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D003370:Coturnix / Q000502:physiology*; D004527:Egg Proteins / Q000378:metabolism*; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism* / Q000502:physiology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D008985:Monensin / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins
chemical_list: D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011500:Protein Synthesis Inhibitors; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D020126:Brefeldin A; D008985:Monensin