A C‐terminal domain, which prevents secretion of the neuroendocrine protein 7B2 in Saccharomyces cerevisiae, inhibits Kex2 yet is processed by the Yap3 protease

FEBS Letters

Stephan, Christine¹  Chaudhuri, Bhabatosh¹ 

[1] Department of Core Drug Discovery Technologies, K-681.146, Ciba-Geigy Ltd., CH-4002 Basel, Switzerland

关键词: 7B2;    Kex2 inhibition;    PC2 convertase;    Processing by Yap3;    Saccharomyces cerevisiae;    Secretion;    7B2;    the neuroendocrine protein 7B2;    human 7B2;    full-length 7B2 (1–185 amino acids);    excluding the signal peptide;    7B2Δ1;    human 7B2(1–137);    7B2Δ2;    human 7B2(1–149);    7B2Δ3;    human 7B2 (1–170);    7B2ss;    signal sequence of the human 7B2 gene;    CYP1p;    the promoter of the S. cerevisiae cytoplasmic cyclophilin gene;    ER;    endoplasmic reticulum;    c GAPDHp;    the promoter of the S. cerevisiae glyceraldhyde-3-phosphate dehydrogenase gene;    IGF1;    human insulin-like growth factor-1;    Invss;    the yeast SUC2 signal sequence;    PCR;    polymerase chain reaction;    PHO5t;    transcription terminator of the yeast PHO5 gene;    POMC;    proopiomelanocortin;   

DOI  :  10.1016/0014-5793(95)00360-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Recent reports reveal that the C-terminal half of the neuroendocrine polypeptide 7B2 selectively inhibits and binds PC2, a mammalian prohormone converting enzyme that is homologous to the yeast pro-α-factor processing protease Kex2. During attempted secretion of the 185 amino-acid human 7B2 in Saccharomyces cerevisiae, we observe that the protein is mostly retained inside the cell. However a mutant polypeptide (7B2Δ1), where the C-terminal 48 amino acids of 7B2 are deleted, is efficiently secreted. Two shorter C-terminal truncations either permit poor secretion or no secretion at all. Surprisingly, full-length 7B2 but not 7B2Δ1 abolishes the catalytic activity of Kex2, indicating that C-terminal residues of 7B2 might also be important for inhibition of the yeast protease. When the KEX2 gene is disrupted, yeast cells unexpectedly secrete a 7B2 variant similar in size to 7B2Δ1, suggesting involvement of the alternate yeast prohormone convertase Yap3 in processing. Secretion is enhanced by overexpression of Yap3 and by the presence of a Lys-Arg residue at the processing site of precursor 7B2. These results purport that, in neuroendocrine cells too, secretion of 7B2 could be mediated by a homologue of Yap3.

【 授权许可】

Unknown