Identification of a dominant endoplasmic reticulum-retention signal in yellow fever virus pre-membrane protein

• Published in: Journal of general virology 2010-02, Vol.91 (2), p.404-414
• Main Authors: Ciczora, Yann, Callens, Nathalie, Seron, Karin, Rouille, Yves, Dubuisson, Jean
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biological and medical sciences; Dimerization; Endoplasmic Reticulum - metabolism; Endoplasmic Reticulum - virology; Fundamental and applied biological sciences. Psychology; HeLa Cells; Humans; Microbiology; Miscellaneous; Molecular Sequence Data; Protein Sorting Signals; Protein Structure, Secondary; Protein Transport; Viral Envelope Proteins - chemistry; Viral Envelope Proteins - genetics; Viral Envelope Proteins - metabolism; Virology; Yellow Fever - metabolism; Yellow Fever - virology; Yellow fever virus; Yellow fever virus - chemistry; Yellow fever virus - genetics; Yellow fever virus - metabolism
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.015339-0

1 Université Lille Nord de France, F-59000 Lille, France 2 CNRS, Institut de Biologie de Lille (UMR8161), F-59021 Lille, France 3 Institut Pasteur de Lille, F-59019 Lille, France Correspondence Jean Dubuisson jean.dubuisson{at}ibl.fr Yellow fever virus (YFV) encodes two envelope proteins, pre-membrane (prM) and envelope (E), that accumulate in the endoplasmic reticulum (ER). The C termini of prM and E form two antiparallel transmembrane -helices that contain ER-retention signals. To understand further the ER retention of the prME heterodimer, we characterized the subcellular localization of chimeric proteins made of a reporter protein fused to the transmembrane segments of YFV envelope proteins. We showed that at least three of the transmembrane segments of the prME heterodimer are ER-retention signals. Interestingly, increasing the length of these -helices led to the export of the chimeric proteins out of the ER. Furthermore, adding a diacidic export signal at the C terminus of the first transmembrane segment of the E protein also induced export to the cell surface. However, adding this export signal at the C terminus of the first transmembrane segment of E in the context of prME did not change the subcellular localization of the prME heterodimer, suggesting the presence of a stronger ER-retention signal outside the first transmembrane segment of E. Importantly, the diacidic export motif added to the C terminus of the first transmembrane segment of the prM protein was not sufficient to export a chimeric protein out of the ER, indicating that this sequence is a dominant ER-retention signal. Together, these data indicate that a combination of several signals of different strengths contributes to the ER retention of the YFV envelope protein heterodimer. These authors contributed equally to this work.