Search results for "COP-Coated Vesicle"
showing 5 items of 5 documents
Hepatitis B Virus Exploits ERGIC-53 in Conjunction with COPII to Exit Cells.
2020
Several decades after its discovery, the hepatitis B virus (HBV) still displays one of the most successful pathogens in human populations worldwide. The identification and characterization of interactions between cellular and pathogenic components are essential for the development of antiviral treatments. Due to its small-sized genome, HBV highly depends on cellular functions to produce and export progeny particles. Deploying biochemical-silencing methods and molecular interaction studies in HBV-expressing liver cells, we herein identified the cellular ERGIC-53, a high-mannose-specific lectin, and distinct components of the endoplasmic reticulum (ER) export machinery COPII as crucial factor…
Sorting signals in the cytosolic tail of plant p24 proteins involved in the interaction with the COPII coat.
2004
The ability of the cytosolic tail of a plant p24 protein to bind COPI and COPII subunits from plant and animal sources in vitro has been examined. We have found that a dihydrophobic motif in the -7,-8 position (relative to the cytosolic carboxy-terminus), which strongly cooperates with a dilysine motif in the -3,-4 position for COPI binding, is required for COPII binding. In addition, we show that COPI and COPII coat proteins from plant cytosol compete for binding to the sorting motifs in these tails. Only in the absence of the dilysine motif in the -3,-4 position or after COPI depletion could we observe COPII binding to the p24 tail. This competition is not observed when using rat liver cy…
Hepatitis B subviral envelope particles use the COPII machinery for intracellular transport via selective exploitation of Sec24A and Sec23B
2020
Hepatitis B virus (HBV) is a leading cause of liver disease. Its success as a human pathogen is related to the immense production of subviral envelope particles (SVPs) contributing to viral persistence by interfering with immune functions. To explore cellular pathways involved in SVP formation and egress, we investigated host-pathogen interactions. Yeast-based proteomics revealed Sec24A, a component of the coat protein complex II (COPII), as an interaction partner of the HBV envelope S domain. To understand how HBV co-opts COPII as a proviral machinery, we studied roles of key Sec proteins in HBV-expressing liver cells. Silencing of Sar1, Sec23, and Sec24, which promote COPII assembly conco…
In vivo Trafficking and Localization of p24 Proteins in Plant Cells
2008
p24 proteins constitute a family of putative cargo receptors that traffic in the early secretory pathway. p24 proteins can be divided into four subfamilies (p23, p24, p25 and p26) by sequence homology. In contrast to mammals and yeast, most plant p24 proteins contain in their cytosolic C-terminus both a dilysine motif in the -3, -4 position and a diaromatic motif in the -7, -8 position. We have previously shown that the cytosolic tail of Arabidopsis p24 proteins has the ability to interact with ARF1 and coatomer (through the dilysine motif) and with COPII subunits (through the diaromatic motif). Here, we establish the localization and trafficking properties of an Arabidopsis thaliana p24 pr…
Endoplasmic Reticulum stress reduces COPII vesicle formation and modifies Sec23a cycling at ERESs
2013
AbstractExit from the Endoplasmic Reticulum (ER) of newly synthesized proteins is mediated by COPII vesicles that bud from the ER at the ER Exit Sites (ERESs). Disruption of ER homeostasis causes accumulation of unfolded and misfolded proteins in the ER. This condition is referred to as ER stress. Previously, we demonstrated that ER stress rapidly impairs the formation of COPII vesicles. Here, we show that membrane association of COPII components, and in particular of Sec23a, is impaired by ER stress-inducing agents suggesting the existence of a dynamic interplay between protein folding and COPII assembly at the ER.