Topogenic Effect of Positively Charged N-terminal Amino Acid in ER Translocation of Yeast α-Factor Precursor

Cell Structure and Function

Myung Ae Lee²  Joonho Choe³  Dennis Shields¹  Kwang Ho Cheong²  Sang Dai Park²  Seung Hwan Hong² 

[1] Department of Anatomy and Structural Biology, Albert Einstein College of Medicine;Department of Molecular Biology and Research Center for Cell Differentiation;Department of Life Science, Korea Advanced Institute of Science and Technology

关键词: Signal peptide;    Yeast α-factor;    ER translocation;    Secretion;   

DOI  :  10.1247/csf.21.175

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(24)Cited-By(3)Expression of fusion proteins between prepro-α-factor and somatostatin (SRIF) in yeast, resulted in the correct processing and secretion of the heterologous 14-amino acid SRIF peptide (1). When the chimeric genes were placed under the control of yeast acid phosphatase (PHO5) promoter, significant amount of an unglycosylated form of the fusion precursor molecule accumulated intracellularly, suggesting disruption of an endoplasmic reticulum-mediated function. We report here that the appearance of the precursor is due to an alteration in the three amino terminal residues of the chimera, i.e., Met-Arg-Phe in native prepro-α-factor is changed to Met-Phe-Lys in the hybrids. The unglycosylated precursor represents a population of molecules that are disrupted at an early stage of targeting to or translocation across the endoplasmic reticulum membrane. Our data demonstrate that the N-terminus plays an important role in topogenesis. Furthermore, these results show that translocation and glycosylation can be uncoupled from protein synthesis ]itin vivo, and therefore can be post-translational events in yeast.

【 授权许可】

Unknown