Heat Shock Induces Preferential Translation of ERGIC-53 and Affects Its Recycling Pathway

• Published in: The Journal of biological chemistry 2004-10, Vol.279 (41), p.42535-42544
• Main Authors: Spatuzza, Carmen, Renna, Maurizio, Faraonio, Raffaella, Cardinali, Giorgia, Martire, Gianluca, Bonatti, Stefano, Remondelli, Paolo
• Format: Article
• Language: English
• Subjects: 5' Untranslated Regions; Base Sequence; Biological Transport; Blotting, Northern; Blotting, Western; Carrier Proteins - metabolism; Cell Line; Centrifugation, Density Gradient; Electrophoresis, Polyacrylamide Gel; Endoplasmic Reticulum - metabolism; Fluorescent Antibody Technique, Indirect; Gene Expression Regulation; Genes, Reporter; Genistein - pharmacology; Glycoproteins - metabolism; Golgi Apparatus - metabolism; Hot Temperature; Humans; Immunoblotting; Immunoprecipitation; Lectins - metabolism; Mannose-Binding Lectins - genetics; Mannose-Binding Lectins - physiology; Membrane Proteins - genetics; Membrane Proteins - physiology; Microscopy, Electron; Microscopy, Fluorescence; Molecular Sequence Data; Promoter Regions, Genetic; Protein Binding; Protein Biosynthesis; Protein Structure, Tertiary; Quercetin - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; RNA - metabolism; RNA, Messenger - metabolism; Signal Transduction; Sucrose - pharmacology; Temperature; Time Factors; Transcriptional Activation; Transfection; Vesicular Transport Proteins
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M401860200

ERGIC-53 is a lectin-like transport receptor protein, which recirculates between the ER and the Golgi complex and is required for the intracellular transport of a restricted number of glycoproteins. We show in this article that ERGIC-53 accumulates during the heat shock response. However, at variance with the unfolded protein response, which results in enhanced transcription of ERGIC-53 mRNA, heat shock leads only to enhanced translation of ERGIC-53 mRNA. In addition, the half-life of the protein does not change during heat shock. Therefore, distinct signal pathways of the cell stress response modulate the ERGIC-53 protein level. Heat shock also affects the recycling pathway of ERGIC-53. The protein rapidly redistributes in a more peripheral area of the cell, in a vesicular compartment that has a lighter sedimentation density on sucrose gradient in comparison to the compartment that contains the majority of ERGIC-53 at 37 °C. This effect is specific, as no apparent reorganization of the endoplasmic reticulum, intermediate compartment and Golgi complex is morphologically detectable in the cells exposed to heat shock. Moreover, the anterograde transport of two unrelated reporter proteins is not affected. Interestingly, MCFD2, which interacts with ERGIC-53 to form a complex required for the ER-to-Golgi transport of specific proteins, is regulated similarly to ERGIC-53 in response to cell stress. These results support the view that ERGIC-53 alone, or in association with MCFD2, plays important functions during cellular response to stress conditions.