Galectin-5 is bound onto the surface of rat reticulocyte exosomes and modulates vesicle uptake by macrophages

Blood ◽  
2010 ◽  
Vol 115 (3) ◽  
pp. 696-705 ◽  
Author(s):  
Céline Barrès ◽  
Lionel Blanc ◽  
Pascale Bette-Bobillo ◽  
Sabine André ◽  
Robert Mamoun ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Vesicles ◽  
Membrane Remodeling ◽  
Membrane Glycoproteins ◽  
Extracellular Medium ◽  
Secretion Pathway ◽  
Reticulocyte Maturation ◽  
Exosomal Sorting ◽  
Multivesicular Endosomes ◽  
Rat Reticulocytes

Abstract Reticulocytes release small membrane vesicles termed exosomes during their maturation into erythrocytes. Exosomes are intraluminal vesicles of multivesicular endosomes released into the extracellular medium by fusion of these endosomal compartments with the plasma membrane. This secretion pathway contributes to reticulocyte plasma membrane remodeling by eliminating certain membrane glycoproteins. We show in this study that galectin-5, although mainly cytosolic, is also present on the cell surface of rat reticulocytes and erythrocytes. In addition, in reticulocytes, it resides in the endosomal compartment. We document galectin-5 translocation from the cytosol into the endosome lumen, leading to its secretion in association with exosomes. Galectin-5 bound onto the vesicle surface may function in sorting galactose-bearing glycoconjugates. Fittingly, we found that Lamp2, a major cellular glycoprotein presenting galectin-reactive poly-N-acetylactosamine chains, is lost during reticulocyte maturation. It is associated with released exosomes, suggestive of binding to galectin-5. Finally, we reveal that the uptake of rat reticulocyte exosomes by macrophages is dependent on temperature and the mechanoenzyme dynamin and that exosome uptake is decreased by adding galectin-5. These data imply galectin-5 functionality in the exosomal sorting pathway during rat reticulocyte maturation.

scholarly journals Aggregation reroutes molecules from a recycling to a vesicle-mediated secretion pathway during reticulocyte maturation

1997 ◽  
Vol 110 (16) ◽  
pp. 1867-1877 ◽  
Author(s):  
M. Vidal ◽  
P. Mangeat ◽  
D. Hoekstra
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Effective Means ◽  
Close Correlation ◽  
Extracellular Medium ◽  
Endosomal Membrane ◽  
Secretion Pathway ◽  
Reticulocyte Maturation ◽  
Specific Proteins ◽  
Induced Aggregation

Endocytosis of the Tf/TfR complex is essentially the only pathway active in maturing reticulocytes, while exosomes, formed by invagination of the endosomal membrane, provide a mechanism to eliminate seemingly obsolescent proteins, including the TfR, when their function is completed. In this study, we examined molecular trafficking in the recycling and exosome-directed pathways during endocytosis in maturing reticulocytes. To this end, the flow of two exogenously inserted fluorescent lipid analogs, N-(N-[6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl]) sphingomyelin (C6-NBD-SM) and N-(lissamine rhodamine B sulfonyl) phosphatidyl ethanolamine (N-Rh-PE) was monitored and compared to that of the transferrin (Tf)/Tf receptor (TfR) complex. Prior to elimination via exosomes, the TfR actively recycles with a half-time of approx. 2 minutes. The recycling kinetics of C6-NBD-SM, as bulk plasma membrane marker, are identical to those of the apoTf/TfR complex, as shown by fluorescence microscopy and biochemical analysis. By contrast, although efficiently internalized along the same pathway, N-Rh-PE does not return to the cell surface. More specifically, sucrose gradient analysis and immunoisolation experiments demonstrated that N-Rh-PE accumulates in exosomes, which are eventually released into the extracellular medium. Fluorometric measurements showed that exogenously inserted N-Rh-PE is present in the reticulocyte plasma membrane as small molecular clusters. Moreover, a close correlation was observed between the fate of crosslinked proteins, including the TfR and acetylcholinesterase (AChE), and the fate of the clustered lipid N-Rh-PE. Thus antibody-induced aggregation of specific proteins like the TfR and AChE, which are normally sorted into exosomes during reticulocyte maturation, enhances their shedding by the exosomal pathway. Taken together, the results support the hypothesis that aggregation of either proteins or lipids act as a general sorting signal for exosomal processing, thereby inhibiting reentry in a recycling pathway and providing an effective means for clearing molecules from the cell surface and their eventual elimination from the cells.

scholarly journals Receptor-mediated endocytosis of transferrin and recycling of the transferrin receptor in rat reticulocytes.

1983 ◽  
Vol 97 (2) ◽  
pp. 329-339 ◽  
Author(s):  
C Harding ◽  
J Heuser ◽  
P Stahl
Keyword(s):  
Plasma Membrane ◽  
Transferrin Receptor ◽  
Intracellular Membrane ◽  
Coated Pits ◽  
Surface Receptors ◽  
Receptor Mediated Endocytosis ◽  
Freeze Dried ◽  
Inner Surface ◽  
Multivesicular Endosomes ◽  
Rat Reticulocytes

At 4 degrees C transferrin bound to receptors on the reticulocyte plasma membrane, and at 37 degrees C receptor-mediated endocytosis of transferrin occurred. Uptake at 37 degrees C exceeded binding at 4 degrees C by 2.5-fold and saturated after 20-30 min. During uptake at 37 degrees C, bound transferrin was internalized into a trypsin-resistant space. Trypsinization at 4 degrees C destroyed surface receptors, but with subsequent incubation at 37 degrees C, surface receptors rapidly appeared (albeit in reduced numbers), and uptake occurred at a decreased level. After endocytosis, transferrin was released, apparently intact, into the extracellular space. At 37 degrees C colloidal gold-transferrin (AuTf) clustered in coated pits and then appeared inside various intracellular membrane-bounded compartments. Small vesicles and tubules were labeled after short (5-10 min) incubations at 37 degrees C. Larger multivesicular endosomes became heavily labeled after longer (20-35 min) incubations. Multivesicular endosomes apparently fused with the plasma membrane and released their contents by exocytosis. None of these organelles appeared to be lysosomal in nature, and 98% of intracellular AuTf was localized in acid phosphatase-negative compartments. AuTf, like transferrin, was released with subsequent incubation at 37 degrees C. Freeze-dried and freeze-fractured reticulocytes confirmed the distribution of AuTf in reticulocytes and revealed the presence of clathrin-coated patches amidst the spectrin coating the inner surface of the plasma membrane. These data suggest that transferrin is internalized via coated pits and vesicles and demonstrate that transferrin and its receptor are recycled back to the plasma membrane after endocytosis.

scholarly journals Mechanism of glycosylation in the Golgi apparatus.

1983 ◽  
Vol 31 (8) ◽  
pp. 1033-1040 ◽  
Author(s):  
B Fleischer
Keyword(s):  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Serum Proteins ◽  
Membrane Vesicles ◽  
Uridine Diphosphate ◽  
Golgi Membrane ◽  
Membrane Glycoproteins ◽  
Plasma Membrane Vesicles ◽  
Golgi Vesicles

A major role of the Golgi apparatus in liver is the terminal glycosylation of secreted serum proteins and of plasma membrane glycoproteins. Galactosyltransferase is a membrane-bound Golgi enzyme that transfers galactose directly from uridine diphosphogalactose (UDP-Gal) to terminal N-acetylglucosamine groups of N-asparagine-linked glycoproteins during secretion. Sialytransferase then transfers sialic acid from cytidine monophosphosialic acid (CMP-NAN) to the newly added terminal galactose of the glycoprotein. In the cell, the transfer reaction must occur on the lumen side of the Golgi membrane. UDP-Gal is synthesized mainly in the cytoplasm and CMP-NAN is synthesized in the nucleus in liver. An important question for understanding the mechanism is, how do these nucleotide sugars gain access to the transferases? A second question involves uridine diphosphate (UDP), a highly inhibitory product of galactosyltransferase. How is UDP removed from the lumen of the Golgi fast enough to prevent product inhibition of the galactosyltransferase? We have shown that isolated Golgi, although vesiculated, retains its original orientation. The vesicles are oriented with greater than 90% of both galactosyltransferase and sialyl-transferase on the luminal side of the vesicles. Using intact vesicles, we can show that UDP-Gal is taken up via a saturable carrier system present in the Golgi membrane. During galactosylation in vitro, UDP formed in the lumen of Golgi vesicles is rapidly converted to UMP by a nucleoside diphosphatase in the lumen. Uridine monophosphate, which is much less inhibitory to the galactosyltransferase than UDP, is then transported out of the lumen by a second carrier and is broken down further to uridine by 5'-nucleotidase on the cytoplasmic side of the Golgi vesicles. The transport of nucleotides appears unique to the Golgi membranes, since neither rough endoplasmic reticulum nor plasma membrane vesicles from rat liver accumulate these nucleotides.

scholarly journals Correlative AFM and fluorescence imaging demonstrate nanoscale membrane remodeling and ring-like and tubular structure formation by septins

Nanoscale ◽  
2021 ◽  
Author(s):  
Anthony Vial ◽  
Cyntia Taveneau ◽  
Luca Costa ◽  
brieuc chauvin ◽  
hussein nasrallah ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Division ◽  
Structure Formation ◽  
Fluorescence Imaging ◽  
Tubular Structure ◽  
Membrane Remodeling

Septins are ubiquitous cytoskeletal filaments that interact with the inner plasma membrane and are essential for cell division in eukaryotes. In cellular contexts, septins are often localized at micrometric gaussian...

scholarly journals Biogenesis of plasma membrane glycoproteins in hepatoma tissue culture cells.

1978 ◽  
Vol 253 (3) ◽  
pp. 965-973 ◽  
Author(s):  
D. Doyle ◽  
H. Baumann ◽  
B. England ◽  
E. Friedman ◽  
E. Hou ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Plasma Membrane ◽  
Membrane Glycoproteins ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Hepatoma Tissue
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