scholarly journals The Mycobacterium tuberculosis phagosome interacts with early endosomes and is accessible to exogenously administered transferrin.

1996 ◽  
Vol 184 (4) ◽  
pp. 1349-1355 ◽  
Author(s):  
D L Clemens ◽  
M A Horwitz
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Culture Medium ◽  
Direct Evidence ◽  
Human Monocyte ◽  
Endocytic Pathway ◽  
Time Dependent ◽  
Late Endosomes ◽  
Latex Beads ◽  
Early Endosomes ◽  
Kinetics Of

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.

scholarly journals Relationship between invariant chain expression and major histocompatibility complex class II transport into early and late endocytic compartments.

1993 ◽  
Vol 177 (3) ◽  
pp. 583-596 ◽  
Author(s):  
P Romagnoli ◽  
C Layet ◽  
J Yewdell ◽  
O Bakke ◽  
R N Germain
Keyword(s):  
Major Histocompatibility Complex ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Endocytic Pathway ◽  
Invariant Chain ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Endocytic Compartments

Invariant chain (Ii), which associates with major histocompatibility complex (MHC) class II molecules in the endoplasmic reticulum, contains a targeting signal for transport to intracellular vesicles in the endocytic pathway. The characteristics of the target vesicles and the relationship between Ii structure and class II localization in distinct endosomal subcompartments have not been well defined. We demonstrate here that in transiently transfected COS cells expressing high levels of the p31 or p41 forms of Ii, uncleaved Ii is transported to and accumulates in transferrin-accessible (early) endosomes. Coexpressed MHC class II is also found in this same compartment. These early endosomes show altered morphology and a slower rate of content movement to later parts of the endocytic pathway. At more moderate levels of Ii expression, or after removal of a highly conserved region in the cytoplasmic tail of Ii, coexpressed class II molecules are found primarily in vesicles with the characteristics of late endosomes/prelysosomes. The Ii chains in these late endocytic vesicles have undergone proteolytic cleavage in the lumenal region postulated to control MHC class II peptide binding. These data indicate that the association of class II with Ii results in initial movement to early endosomes. At high levels of Ii expression, egress to later endocytic compartments is delayed and class II-Ii complexes accumulate together with endocytosed material. At lower levels of Ii expression, class II-Ii complexes are found primarily in late endosomes/prelysosomes. These data provide evidence that the route of class II transport to the site of antigen processing and loading involves movement through early endosomes to late endosomes/prelysosomes. Our results also reveal an unexpected ability of intact Ii to modify the structure and function of the early endosomal compartment, which may play a role in regulating this processing pathway.

scholarly journals Recycling pathways of glucosylceramide in BHK cells: distinct involvement of early and late endosomes

1992 ◽  
Vol 103 (4) ◽  
pp. 1139-1152
Author(s):  
J.W. Kok ◽  
K. Hoekstra ◽  
S. Eskelinen ◽  
D. Hoekstra
Keyword(s):  
Plasma Membrane ◽  
Intracellular Ph ◽  
Brefeldin A ◽  
Fluid Phase ◽  
Endocytic Pathway ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Recycling Pathway ◽  
Golgi Network ◽  
Extensive Involvement

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.

scholarly journals Identification of a membrane glycoprotein found primarily in the prelysosomal endosome compartment.

1991 ◽  
Vol 112 (2) ◽  
pp. 245-255 ◽  
Author(s):  
J E Park ◽  
J M Lopez ◽  
E B Cluett ◽  
W J Brown
Keyword(s):  
Lysosomal Enzymes ◽  
Endocytic Pathway ◽  
Membrane Glycoprotein ◽  
Cell Fractionation ◽  
Density Fractions ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Acidic Compartment ◽  
Intracellular Vesicles ◽  
Secondary Lysosomes

Cells contain an intracellular compartment that serves as both the "prelysosomal" delivery site for newly synthesized lysosomal enzymes by the mannose 6-phosphate (Man6P) receptor and as a station along the endocytic pathway to lysosomes. We have obtained mAbs to a approximately 57-kD membrane glycoprotein, (called here plgp57), found predominantly in this prelysosomal endosome compartment. This conclusion is supported by the following results: (a) plgp57 was primarily found in a population of late endosomes that were located just distal to the 20 degrees C block site in the endocytic pathway to lysosomes (approximately 83% of the prelysosomes were positive for plgp57 but less than 5% of the early endosomes had detectable amounts of this marker); (b) plgp57 and the cation-independent (CI) Man6P receptor were located in many of the same intracellular vesicles; (c) plgp57 was found in the membranes of an acidic compartment; (d) immunoelectron microscopy showed that plgp57 was located in characteristic multilamellar- and multivesicular-type vacuoles believed to be prelysosomal endosomes; and (e) cell fractionation studies demonstrated that plgp57 was predominantly found in low density organelles which comigrated with late endosomes and CI Man6P receptors, and only approximately 10-15% of the antigen was found in high density fractions containing the majority of secondary lysosomes. These results indicate that plgp57 is a novel marker for a unique prelysosomal endosome compartment that is the site of confluence of the endocytic and biosynthetic pathways to lysosomes.

scholarly journals Fusion of sequentially internalized vesicles in alveolar macrophages.

1990 ◽  
Vol 110 (4) ◽  
pp. 1013-1022 ◽  
Author(s):  
D M Ward ◽  
D P Hackenyos ◽  
J Kaplan
Keyword(s):  
Endocytic Pathway ◽  
Receptor Complexes ◽  
Intracellular Vesicle ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Changing Patterns ◽  
Intracellular Vesicle Transport ◽  
Shift Technique ◽  
Ligand Addition ◽  
Density Shift

Previously we reported that internalized ligand-receptor complexes are transported within the alveolar macrophage at a rate that is independent of the ligand and/or receptor but is dependent on the endocytic apparatus (Ward, D. M., R. S. Ajioka, and J. Kaplan. 1989. J. Biol. Chem. 264:8164-8170). To probe the mechanism of intracellular vesicle transport, we examined the ability of vesicles internalized at different times to fuse. The mixing of ligands internalized at different times was studied using the 3,3'-diaminobenzidine/horseradish peroxidase density shift technique. The ability of internalized vesicles to fuse was dependent upon their location in the endocytic pathway. When ligands were administered as tandem pulses a significant amount of mixing (20-40%) of vesicular contents was observed. The pattern of mixing was independent of the ligands employed (transferrin, mannosylated BSA, or alpha macroglobulin), the order of ligand addition, and temperature (37 degrees C or 28 degrees C). Fusion was restricted to a brief period immediately after internalization. The amount of fusion in early endosomes did not increase when cells, given tandem pulses, were chased such that the ligands further traversed the early endocytic pathway. Little fusion, also, was seen when a chase was interposed between the two ligand pulses. The temporal segregation of vesicle contents seen in early endosomes was lost within late endosomes. Extensive mixing of vesicle contents was observed in the later portion of the endocytic pathway. This portion of the pathway is defined by the absence of internalized transferrin and is composed of ligands en route to lysosomes. Incubation of cells in iso-osmotic medium in which Na+ was replaced by K+ inhibited movement of internalized ligands to the lysosome, resulting in ligand accumulation within the late endocytic pathway. The accumulation of ligand was correlated with extensive mixing of sequentially internalized ligands. Although significant amounts of ligand degradation were observed, this compartment was devoid of conventional lysosomal markers such as acid glycosidases. These results indicate changing patterns of vesicle fusion within the endocytic pathway, with a complete loss of temporal ligand segregation in a prelysosomal compartment.

scholarly journals Role of the RAB7 Protein in Tumor Progression and Cisplatin Chemoresistance

Cancers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1096 ◽  
Author(s):  
Guerra ◽  
Bucci
Keyword(s):  
Cancer Progression ◽  
Extracellular Vesicle ◽  
Endocytic Pathway ◽  
Cellular Processes ◽  
Molecular Events ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Cellular Context ◽  
Guanosine Triphosphatase

RAB7 is a small guanosine triphosphatase (GTPase) extensively studied as regulator of vesicular trafficking. Indeed, its role is fundamental in several steps of the late endocytic pathway, including endosome maturation, transport from early endosomes to late endosomes and lysosomes, clustering and fusion of late endosomes and lysosomes in the perinuclear region and lysosomal biogenesis. Besides endocytosis, RAB7 is important for a number of other cellular processes among which, autophagy, apoptosis, signaling, and cell migration. Given the importance of RAB7 in these cellular processes, the interest to study the role of RAB7 in cancer progression is widely grown. Here, we describe the current understanding of oncogenic and oncosuppressor functions of RAB7 analyzing cellular context and other environmental factors in which it elicits pro and/or antitumorigenic effects. We also discuss the role of RAB7 in cisplatin resistance associated with its ability to regulate the late endosomal pathway, lysosomal biogenesis and extracellular vesicle secretion. Finally, we examined the potential cancer therapeutic strategies targeting the different molecular events in which RAB7 is involved.

Internalisation of desmosomes and their entry into the endocytic pathway via late endosomes in MDCK cells. Possible mechanisms for the modulation of cell adhesion by desmosomes during development

1993 ◽  
Vol 106 (4) ◽  
pp. 1115-1130 ◽  
Author(s):  
I.D. Burdett
Keyword(s):  
Cell Adhesion ◽  
Mdck Cells ◽  
Immunogold Labelling ◽  
Mouse Kidney ◽  
Vacuolar Membrane ◽  
Endocytic Pathway ◽  
General Mechanism ◽  
Frozen Sections ◽  
Late Endosomes ◽  
Early Endosomes

MDCK cells grown in media with normal levels of Ca2+ (approximately 2 mM) contain internalised desmosomes, referred to as desmosome-associated vacuoles (DAVs). The DAVs consist of one to three plaques retained in the plane of a surrounding vacuolar membrane, and their entry into the endocytic pathway has been investigated using HRP, cationized ferritin and BSA/gold in combination with electron microscopy and immunogold labelling of frozen sections. Endocytic tracers supplied from the apical and basolateral surfaces to filter-grown MDCK cells met in a common perinuclear compartment but DAVs were not labelled during short (5-30 minutes) pulses of marker, whether applied apically or basolaterally. Only when the tracers were taken up from the basolateral surface and then chased for periods of 2–18 hours, were DAVs labelled. It is proposed that entry of an endocytic tracer to DAVs occurs by the association of the desmosomal vacuole with late endosomes. Immunolabelling studies with antibodies to desmosomal components (to Dsg, DPI/II), to HRP and to the cation-independent mannose 6-phosphate receptor (MPR), confirmed that Dsg and DPI/II are located within DAVs and late endosomes, but not in early endosomes. Passage of Dsg, but to a lesser extent DPI/II, was detected in MPR- structures (lysosomes). DAV-like structures have also been observed in developing tissues such as mouse kidney. Such engulfment may provide a general mechanism for handling insoluble junctional proteins, particularly where rapid morphogenetic changes are occurring in the pattern of cell-cell adhesion.

Evidence for retrograde traffic between terminal lysosomes and the prelysosomal/late endosome compartment

1994 ◽  
Vol 107 (1) ◽  
pp. 145-157 ◽  
Author(s):  
A. Jahraus ◽  
B. Storrie ◽  
G. Griffiths ◽  
M. Desjardins
Keyword(s):  
Light Microscope ◽  
Retrograde Transport ◽  
Late Endosome ◽  
Endocytic Pathway ◽  
Fusion Event ◽  
Microtubule Network ◽  
Cell Biol ◽  
Late Endosomes ◽  
Latex Beads ◽  
Retrograde Traffic

We have investigated the interactions occurring between the prelysosomal compartment, PLC/late endosome, and terminal lysosomes using an approach that allowed us to internalize and deliver specific tracers to these compartments, and look for evidence of their meeting. After internalization of sucrose, the lysosomes (sucrosomes), but not the PLC/late endosomes, became significantly swollen and visible in the light microscope. If invertase is then added to the medium it reaches the lysosomes where it cleaves sucrose into fructose and glucose. These sugars, unlike sucrose, can be transported into the cytosol, resulting in the disappearance of the sucrosomes. We previously showed that phagocytosed latex beads are delivered specifically to, and reside in, the PLC/late endosome, a stage earlier than the lysosomes in the endocytic pathway (Rabinowitz et al. (1992) J. Cell Biol. 116, 95–112). In the present study, we demonstrate that invertase conjugated to the latex beads, and thus immobilized in late endosomes, has access to the sucrose present in the more distal lysosomes. Experiments using nocodazole indicate that this retrograde fusion event requires the presence of an intact microtubule network. The simplest interpretation of our results is that the two compartments fuse, allowing for a retrograde transport of sucrose from the lysosomes to the PLC/late endosomes.

scholarly journals Control of Ste6 Recycling by Ubiquitination in the Early Endocytic Pathway in Yeast

2005 ◽  
Vol 16 (6) ◽  
pp. 2809-2821 ◽  
Author(s):  
Tamara Krsmanović ◽  
Agnes Pawelec ◽  
Tobias Sydor ◽  
Ralf Kölling
Keyword(s):  
Endocytic Pathway ◽  
Wild Type ◽  
Endocytic Recycling ◽  
Sorting Nexin ◽  
Class D ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Internal Structures ◽  
Vacuolar Protein ◽  
Polar Distribution

We present evidence that ubiquitination controls sorting of the ABC-transporter Ste6 in the early endocytic pathway. The intracellular distribution of Ste6 variants with reduced ubiquitination was examined. In contrast to wild-type Ste6, which was mainly localized to internal structures, these variants accumulated at the cell surface in a polar manner. When endocytic recycling was blocked by Ypt6 inactivation, the ubiquitination deficient variants were trapped inside the cell. This indicates that the polar distribution is maintained dynamically through endocytic recycling and localized exocytosis (“kinetic polarization”). Ste6 does not appear to recycle through late endosomes, because recycling was not blocked in class E vps (vacuolar protein sorting) mutants (Δvps4, Δvps27), which are affected in late endosome function and in the retromer mutant Δvps35. Instead, recycling was partially affected in the sorting nexin mutant Δsnx4, which serves as an indication that Ste6 recycles through early endosomes. Enhanced recycling of wild-type Ste6 was observed in class D vps mutants (Δpep12, Δvps8, and Δvps21). The identification of putative recycling signals in Ste6 suggests that recycling is a signal-mediated process. Endocytic recycling and localized exocytosis could be important for Ste6 polarization during the mating process.

scholarly journals APPL endosomes are not obligatory endocytic intermediates but act as stable cargo-sorting compartments

2015 ◽  
Vol 211 (1) ◽  
pp. 123-144 ◽  
Author(s):  
Inna Kalaidzidis ◽  
Marta Miaczynska ◽  
Marta Brewińska-Olchowik ◽  
Anna Hupalowska ◽  
Charles Ferguson ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Models ◽  
Endocytic Pathway ◽  
Distinct Population ◽  
Primary Mechanism ◽  
Cargo Transport ◽  
Early Endosomes ◽  
Kinetics Of ◽  
Vesicular Compartment ◽  
Over Time

Endocytosis allows cargo to enter a series of specialized endosomal compartments, beginning with early endosomes harboring Rab5 and its effector EEA1. There are, however, additional structures labeled by the Rab5 effector APPL1 whose role in endocytic transport remains unclear. It has been proposed that APPL1 vesicles are transport intermediates that convert into EEA1 endosomes. Here, we tested this model by analyzing the ultrastructural morphology, kinetics of cargo transport, and stability of the APPL1 compartment over time. We found that APPL1 resides on a tubulo-vesicular compartment that is capable of sorting cargo for recycling or degradation and that displays long lifetimes, all features typical of early endosomes. Fitting mathematical models to experimental data rules out maturation of APPL1 vesicles into EEA1 endosomes as a primary mechanism for cargo transport. Our data suggest instead that APPL1 endosomes represent a distinct population of Rab5-positive sorting endosomes, thus providing important insights into the compartmental organization of the early endocytic pathway.

scholarly journals The giant organelles in beige and Chediak-Higashi fibroblasts are derived from late endosomes and mature lysosomes.

1993 ◽  
Vol 178 (6) ◽  
pp. 1845-1856 ◽  
Author(s):  
J K Burkhardt ◽  
F A Wiebel ◽  
S Hester ◽  
Y Argon
Keyword(s):  
Cell Lines ◽  
Secretory Granules ◽  
Mutant Cell ◽  
Endocytic Pathway ◽  
Wild Type ◽  
Marker Proteins ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Acidic Organelles ◽  
Respective Wild Type

Chediak-Higashi Syndrome (CHS) is an autosomal recessive disease affecting secretory granules and lysosomes-like organelles. In CHS fibroblasts, acidic organelles are abnormally large and clustered in the perinuclear area. We have analyzed fibroblast cell lines from a CHS patient and from the murine model for CHS, the beige mouse, to determine which lysosome-like compartments are affected. Uptake of neutral red showed that in both beige and CHS cell lines, the acidic organelles were markedly clustered in the perinuclear region of the cells. Giant organelles (> 4 microns) were observed in a fraction of the cells, and these were more dramatic in the beige fibroblasts than in the CHS fibroblasts. The total dye uptake of both mutant cell lines was similar to their respective wild type fibroblasts, suggesting that the overall volume of acidic compartments is unaffected by the disorder. Histochemistry and immunofluorescence showed that the giant organelles in both beige and CHS fibroblasts were positive for cathepsin D, lysosome-associated membrane protein (LAMP) 1, LAMP 2, and a 120-kD lysosomal glycoprotein, all marker proteins for late endosomes and lysosomes. The giant organelles were also negative for transferrin receptor and mannose-6-phosphate receptor, and most of them were also negative for rab 7. This distribution of marker proteins shows that the giant organelles in both beige and CHS are derived from late compartments of the endocytic pathway. This conclusion was confirmed using endocytic tracers. BSA was transported to the giant organelles, but only after long incubation times, and only at 37 degrees C. alpha 2-Macroglobulin was taken up and degraded at similar rates by CHS or beige cells and their respective wild type control cells. Taken together, our results indicate that the mutation in CHS specifically affects late endosomes and lysosomes, with little or no effect on early endosomes. Although the mutation clearly causes mislocalization of these organelles, it appears to have little effect on their endocytic and degradative functions.

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