Anomalous diffusion reports on the interaction of misfolded proteins with the quality control machinery in the endoplasmic reticulum

• Verfasst von: Malchus, Nina [VerfasserIn]
• Verfasst von: Weiß, Matthias [VerfasserIn]
• Titel: Anomalous diffusion reports on the interaction of misfolded proteins with the quality control machinery in the endoplasmic reticulum
• Verf.angabe: Nina Malchus and Matthias Weiss
• E-Jahr: 2010
• Jahr: 17 August 2010
• Umfang: 8 S.
• Fussnoten: Gesehen am 02.05.2023
• Titel Quelle: Enthalten in: Biophysical journal
• Ort Quelle: Cambridge, Mass. : Cell Press, 1960
• Jahr Quelle: 2010
• Band/Heft Quelle: 99(2010), 4 vom: Aug., Seite 1321-1328
• ISSN Quelle: 1542-0086
• DOI: doi:10.1016/j.bpj.2010.06.020
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 184411077X

Abstract

A multitude of transmembrane proteins enters the endoplasmic reticulum (ER) as unfolded polypeptide chains. During their folding process, they interact repetitively with the ER's quality control machinery. Here, we have used fluorescence correlation spectroscopy to probe these interactions for a prototypical transmembrane protein, VSVG ts045, in vivo. While both folded and unfolded VSVG ts045 showed anomalous diffusion, the unfolded protein had a significantly stronger anomaly. This difference subsided when unfolded VSVG ts045 was in a complex with its chaperone calnexin, or when a mutant form of VSVG ts045 with only one glycan was used. Our experimental data and accompanying simulations suggest that the folding sensor of the quality control (UGT1) oligomerizes unfolded VSVG ts045, leading to a more anomalous/obstructed diffusion. In contrast, calnexin dissolves the oligomers, rendering unfolded VSVG ts045 more mobile, and hence prevents poisoning of the ER.