scholarly journals Dynamic Dissection of the Endocytosis of Porcine Epidemic Diarrhea Coronavirus Cooperatively Mediated by Clathrin and Caveolae as Visualized by Single-Virus Tracking

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Yangyang Li ◽  
Jian Wang ◽  
Wei Hou ◽  
Yanke Shan ◽  
Shouyu Wang ◽  
...  

ABSTRACT Coronaviruses (CoVs) have caused severe diseases in humans and animals. Endocytic pathways, such as clathrin-mediated endocytosis (CME) and caveolae-mediated endocytosis (CavME), play an important role for CoVs to penetrate the cell membrane barrier. In this study, a novel CoV entry manner is unraveled in which clathrin and caveolae can cooperatively mediate endocytosis of porcine epidemic diarrhea coronavirus (PEDV). Using multicolor live-cell imaging, the dynamics of the fluorescently labeled clathrin structures, caveolae structures, and PEDV were dissected. During CavME of PEDV, we found that clathrin structures can fuse with caveolae near the cell plasma membrane, and the average time of PEDV penetrating the cell membrane was within ∼3 min, exhibiting a rapid course of PEDV entry. Moreover, based on the dynamic recruitment of clathrin and caveolae structures and viral motility, the direct evidence also shows that about 20% of PEDVs can undergo an abortive entry via CME and CavME. Additionally, the dynamic trafficking of PEDV from clathrin and caveolae structures to early endosomes, and from early endosomes to late endosomes, and viral fusion were directly dissected, and PEDV fusion mainly occurred in late endosomes within ∼6.8 min after the transport of PEDV to late endosomes. Collectively, this work systematically unravels the early steps of PEDV infection, which expands our understanding of the mechanism of CoV infection. IMPORTANCE Emerging and re-emerging coronaviruses cause serious human and animal epidemics worldwide. For many enveloped viruses, including coronavirus, it is evident that breaking the plasma membrane barrier is a pivotal and complex process, which contains multiple dynamic steps. Although great efforts have been made to understand the mechanisms of coronavirus endocytic pathways, the direct real-time imaging of individual porcine epidemic diarrhea coronavirus (PEDV) internalization has not been achieved yet. In this study, we not only dissected the kinetics of PEDV entry via clathrin-mediated endocytosis and caveolae-mediated endocytosis and the kinetics of endosome trafficking and viral fusion but also found a novel productive coronavirus entry manner in which clathrin and caveolae can cooperatively mediate endocytosis of PEDV. Moreover, we uncovered the existence of PEDV abortive endocytosis. In summary, the productive PEDV entry via the cooperation between clathrin and caveolae structures and the abortive endocytosis of PEDV provide new insights into coronavirus penetrating the plasma membrane barrier.

1992 ◽  
Vol 103 (4) ◽  
pp. 1139-1152
Author(s):  
J.W. Kok ◽  
K. Hoekstra ◽  
S. Eskelinen ◽  
D. Hoekstra

Recycling pathways of the sphingolipid glucosylceramide were studied by employing a fluorescent analog of glucosylceramide, 6(-)[N-(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]hexanoylglucosyl sphingosine (C6-NBD-glucosylceramide). Direct recycling of the glycolipid from early endosomes to the plasma membrane occurs, as could be shown after treating the cells with the microtubule-disrupting agent nocodazole, which causes inhibition of the glycolipid's trafficking from peripheral early endosomes to centrally located late endosomes. When the microtubuli are intact, at least part of the glucosylceramide is transported from early to late endosomes together with ricin. Interestingly, also N-(lissamine rhodamine B sulfonyl)phosphatidylethanolamine (N-Rh-PE), a membrane marker of the fluid-phase endocytic pathway, is transported to this endosomal compartment. However, in contrast to both ricin and N-Rh-PE, the glucosylceramide can escape from this organelle and recycle to the plasma membrane. Monensin and brefeldin A have little effect on this recycling pathway, which would exclude extensive involvement of early Golgi compartments in recycling. Hence, the small fraction of the glycolipid that colocalizes with transferrin (Tf) in the Golgi area might directly recycle via the trans-Golgi network. When the intracellular pH was lowered to 5.5, recycling was drastically reduced, in accordance with the impeding effect of low intracellular pH on vesicular transport during endocytosis and in the biosynthetic pathway. Our results thus demonstrate the existence of at least two recycling pathways for glucosylceramide and indicate the relevance of early endosomes in recycling of both proteins and lipids.


2000 ◽  
Vol 11 (10) ◽  
pp. 3289-3298 ◽  
Author(s):  
Wolfram Antonin ◽  
Claudia Holroyd ◽  
Ritva Tikkanen ◽  
Stefan Höning ◽  
Reinhard Jahn

Endobrevin/VAMP-8 is an R-SNARE localized to endosomes, but it is unknown in which intracellular fusion step it operates. Using subcellular fractionation and quantitative immunogold electron microscopy, we found that endobrevin/VAMP-8 is present on all membranes known to communicate with early endosomes, including the plasma membrane, clathrin-coated pits, late endosomes, and membranes of thetrans-Golgi network. Affinity-purified antibodies that block the ability of endobrevin/VAMP-8 to form SNARE core complexes potently inhibit homotypic fusion of both early and late endosomes in vitro. Fab fragments were as active as intact immunoglobulin Gs. Recombinant endobrevin/VAMP-8 inhibited both fusion reactions with similar potency. We conclude that endobrevin/VAMP-8 operates as an R-SNARE in the homotypic fusion of early and late endosomes.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Makoto Nagano ◽  
Junko Y. Toshima ◽  
Daria Elisabeth Siekhaus ◽  
Jiro Toshima

AbstractEarly endosomes, also called sorting endosomes, are known to mature into late endosomes via the Rab5-mediated endolysosomal trafficking pathway. Thus, early endosome existence is thought to be maintained by the continual fusion of transport vesicles from the plasma membrane and the trans-Golgi network (TGN). Here we show instead that endocytosis is dispensable and post-Golgi vesicle transport is crucial for the formation of endosomes and the subsequent endolysosomal traffic regulated by yeast Rab5 Vps21p. Fittingly, all three proteins required for endosomal nucleotide exchange on Vps21p are first recruited to the TGN before transport to the endosome, namely the GEF Vps9p and the epsin-related adaptors Ent3/5p. The TGN recruitment of these components is distinctly controlled, with Vps9p appearing to require the Arf1p GTPase, and the Rab11s, Ypt31p/32p. These results provide a different view of endosome formation and identify the TGN as a critical location for regulating progress through the endolysosomal trafficking pathway.


1989 ◽  
Vol 109 (6) ◽  
pp. 3243-3258 ◽  
Author(s):  
M Bomsel ◽  
K Prydz ◽  
R G Parton ◽  
J Gruenberg ◽  
K Simons

In this paper, we have characterized the apical and basolateral endocytic pathways of epithelial MDCK cells grown on filters. The three-dimensional organization of the endocytic compartments was analyzed by confocal microscopy after internalization of a fluorescent fluid-phase marker from either side of the cell layer. After 5 min of internalization, distinct sets of apical and basolateral early endosomes were observed lining the plasma membrane domain from which internalization had occurred. At later time points, the apical and the basolateral endocytic pathways were shown to converge in the perinuclear region. Mixing of two different fluorescent markers could be detected after their simultaneous internalization from opposite sides of the cell layer. The extent of the meeting was quantitated by measuring the amount of complex formed intracellularly between avidin internalized from the apical side and biotinylated horseradish peroxidase (HRP) from the basolateral side. After 15 min, 14% of the avidin marker was complexed with the biotinylated HRP and this value increased to 50% during a subsequent chase of 60 min in avidin-free medium. We also determined the kinetics of fluid internalization, recycling, transcytosis, and intracellular retention using HRP as a marker. Fluid was internalized with the same rates from either surface domain (1.2 x 10(-4) microns 3/min per microns 2 of surface area). However, significant differences were observed for each pathway in the amounts and kinetics of marker recycled and transcytosed. The content of apical early endosomes was primarily recycled and transcytosed (45% along Bach route after 1 h internalization), whereas delivery to late endocytic compartments was favored from the basolateral early endosome (77% after 1 h). Our results demonstrate that early apical and basolateral endosomes are functionally and topologically distinct, but that the endocytic pathways converge at later stages in the perinuclear region of the cell.


1996 ◽  
Vol 184 (4) ◽  
pp. 1349-1355 ◽  
Author(s):  
D L Clemens ◽  
M A Horwitz

Previous studies have demonstrated that the Mycobacterium tuberculosis phagosome in human monocyte-derived macrophages acquires markers of early and late endosomes, but direct evidence of interaction of the M. tuberculosis phagosome with the endosomal compartment has been lacking. Using the cryosection immunogold technique, we have found that the M. tuberculosis phagosome acquires exogenously added transferrin in a time-dependent fashion. Near-maximal acquisition of transferrin occurs within 15 min, kinetics of acquisition consistent with interaction of the M. tuberculosis phagosome with early endosomes. Transferrin is chased out of the M. tuberculosis phagosome by incubation of the infected macrophages in culture medium lacking human transferrin. Phagosomes containing latex beads or heat-killed M. tuberculosis, on the other hand, do not acquire staining for transferrin. These and other findings demonstrate that M. tuberculosis arrests the maturation of its phagosome at a stage at which the phagosome interacts with early and late endosomes, but not with lysosomes. The transferrin endocytic pathway potentially provides a novel route for targeting antimicrobials to the M. tuberculosis phagosome.


2001 ◽  
Vol 114 (10) ◽  
pp. 1935-1947 ◽  
Author(s):  
R. Zahn ◽  
B.J. Stevenson ◽  
S. Schroder-Kohne ◽  
B. Zanolari ◽  
H. Riezman ◽  
...  

end13-1 was isolated in a screen for endocytosis mutants and has been shown to have a post-internalisation defect in endocytic transport as well as a defect in vacuolar protein sorting (Vps(-) phenotype), leading to secretion of newly synthesised vacuolar proteins. Here we demonstrate that END13 is identical to VPS4, encoding an AAA (ATPase associated with a variety of cellular activities)-family ATPase. We also report that the end13-1 mutation is a serine 335 to phenylalanine substitution in the AAA-ATPase domain of End13p/Vps4p. It has been reported that mutant cells lacking End13p/Vps4p (end13(vps4)((Dgr;)) accumulate endocytosed marker dyes, plasma membrane receptors and newly synthesised vacuolar hydrolase precursors in an endosomal compartment adjacent to the vacuole (prevacuolar compartment, or PVC). We find, however, that the end13 mutants have defects in transport of endocytosed fluorescent dyes, plasma membrane receptors and ligands from small peripherally located early endosomes to larger late endosomes, which are often located adjacent to the vacuole. Our results indicate that End13p/Vps4p may play an important role in multiple steps of membrane traffic through the endocytic pathway.


1992 ◽  
Vol 119 (1) ◽  
pp. 123-137 ◽  
Author(s):  
R G Parton ◽  
K Simons ◽  
C G Dotti

The endocytic pathways from the axonal and dendritic surfaces of cultured polarized hippocampal neurons were examined. The dendrites and cell body contained extensive networks of tubular early endosomes which received endocytosed markers from the somatodendritic domain. In axons early endosomes were confined to presynaptic terminals and to varicosities. The somatodendritic but not the presynaptic early endosomes were labeled by internalized transferrin. In contrast to early endosomes, late endosomes and lysosomes were shown to be predominantly located in the cell body. Video microscopy was used to follow the transport of internalized markers from the periphery of axons and dendrites back to the cell body. Labeled structures in both domains moved unidirectionally by retrograde fast transport. Axonally transported organelles were sectioned for EM after video microscopic observation and shown to be large multivesicular body-like structures. Similar structures accumulated at the distal side of an axonal lesion. Multivesicular bodies therefore appear to be the major structures mediating transport of endocytosed markers between the nerve terminals and the cell body. Late endocytic structures were also shown to be highly mobile and were observed moving within the cell body and proximal dendritic segments. The results show that the organization of the endosomes differs in the axons and dendrites of cultured rat hippocampal neurons and that the different compartments or stages of the endocytic pathways can be resolved spatially.


2013 ◽  
Vol 304 (11) ◽  
pp. G980-G990 ◽  
Author(s):  
S. Lissner ◽  
C.-J. Hsieh ◽  
L. Nold ◽  
K. Bannert ◽  
P. Bodammer ◽  
...  

Electroneutral NaCl absorption in the ileum and colon is mediated by downregulated in adenoma (DRA) (Cl-/HCO3- exchanger; SLC26A3) and Na+/H+ exchanger 3 (NHE3, SLC9A3). Surface expression of transport proteins undergoes basal and regulated recycling by endo- and exocytosis. Expression and activity of DRA in the plasma membrane depend on intact lipid rafts, phosphatidylinositol 3-kinase (PI3-kinase), and the PDZ interaction of DRA. However, it is unknown how the PDZ interaction of DRA affects its trafficking to the cell surface. Therefore, the (re)cycling pathway of DRA was investigated in HEK cells stably expressing enhanced green fluorescent protein (EGFP)-DRA or EGFP-DRA-ETKFminus (a mutant lacking the PDZ interaction motif). Early, late, and recycling endosomes were immunoisolated by precipitating stably transfected mCherry-hemagglutinin (HA)-Rab5a, -7a, or -11a. EGFP-DRA and EGFP-DRA-ETKFminus were equally present in early endosomes. In recycling endosomes, wild-type DRA was preferentially present, whereas, in late endosomes, DRA-ETKF-minus dominated. Correspondingly, EGFP-DRA colocalized with mCherry-HA-Rab11a in recycling endosomes, whereas EGFP-DRA-ETKFminus colocalized with mCherry-HA-Rab7a in late endosomes. Functionally, this different distribution was reflected by a shorter half-life of the mutant DRA. Transient expression of dominant-negative Rab11aS25N inhibited the activity (-17%, P < 0.05) and the cell surface expression of DRA (-30%, P < 0.05). Transient transfection of Rab4a or its dominant-negative mutant Rab4aS22N was without effect and thus excluded participation of the rapid recycling pathway. Taken together, the PDZ interaction of DRA facilitates its movement into Rab11a-positive recycling endosomes, from where it is inserted in the plasma membrane. A scenario emerges where specific PDZ adaptor proteins are present along several compartments of the endocytosis-recycling pathway.


2002 ◽  
Vol 159 (4) ◽  
pp. 625-635 ◽  
Author(s):  
Jyoti K. Jaiswal ◽  
Norma W. Andrews ◽  
Sanford M. Simon

Similar to its role in secretory cells, calcium triggers exocytosis in nonsecretory cells. This calcium-dependent exocytosis is essential for repair of membrane ruptures. Using total internal reflection fluorescence microscopy, we observed that many organelles implicated in this process, including ER, post-Golgi vesicles, late endosomes, early endosomes, and lysosomes, were within 100 nm of the plasma membrane (in the evanescent field). However, an increase in cytosolic calcium led to exocytosis of only the lysosomes. The lysosomes that fused were predominantly predocked at the plasma membrane, indicating that calcium is primarily responsible for fusion and not recruitment of lysosomes to the cell surface.


2005 ◽  
Vol 393 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Edward Leithe ◽  
Andreas Brech ◽  
Edgar Rivedal

Gap junctions are plasma membrane areas enriched in channels that provide direct intercellular communication. Gap junctions have a high turnover rate; however, the mechanisms by which gap junctions are degraded are incompletely understood. In the present study, we show that in response to phorbol ester treatment, the gap junction channel protein Cx43 (connexin43) is redistributed from the plasma membrane to intracellular vesicles positive for markers for early and late endosomes and for the endolysosomal protease cathepsin D. Immunoelectron microscopy studies indicate that the double membranes of internalized gap junctions undergo separation and cutting, resulting in multivesicular endosomes enriched in Cx43 protein. Using preloading of BSA–gold conjugates to mark lysosomes, we provide evidence suggesting that the degradation process of the double-membrane structure of annular gap junctions occurs prior to transport of Cx43 to the lysosome. The results further suggest that bafilomycin A1, an inhibitor of vacuolar H+-ATPases, causes accumulation of Cx43 in early endosomes. Taken together, these findings indicate that internalized gap junctions undergo a maturation process from tightly sealed double-membrane vacuoles to connexin-enriched multivesicular endosomes with a single limiting membrane. The results further suggest that along with the processing of the double-membrane structure of annular gap junctions, connexins are trafficked via early and late endosomes, finally resulting in their endolysosomal degradation.


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