Graça Raposo

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Exosomes are small membrane vesicles found in cell culture supernatants and in different biological fluids. Exosomes form in a particular population of endosomes, called multivesicular bodies (MVBs), by inward budding into the lumen of the compartment. Upon fusion of MVBs with the plasma membrane, these internal vesicles are secreted. Exosomes possess a(More)
Cells release into the extracellular environment diverse types of membrane vesicles of endosomal and plasma membrane origin called exosomes and microvesicles, respectively. These extracellular vesicles (EVs) represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins,(More)
Antigen-presenting cells contain a specialized late endocytic compartment, MIIC (major histocompatibility complex [MHC] class II-enriched compartment), that harbors newly synthesized MHC class II molecules in transit to the plasma membrane. MIICs have a limiting membrane enclosing characteristic internal membrane vesicles. Both the limiting membrane and the(More)
Cells release different types of vesicular carriers of membrane and cytosolic components into the extracellular space. These vesicles are generated within the endosomal system or at the plasma membrane. Among the various kinds of secreted membrane vesicles, exosomes are vesicles with a diameter of 40-100 nm that are secreted upon fusion of multivesicular(More)
In the 1980s, exosomes were described as vesicles of endosomal origin secreted from reticulocytes. Interest increased around these extracellular vesicles, as they appeared to participate in several cellular processes. Exosomes bear proteins, lipids, and RNAs, mediating intercellular communication between different cell types in the body, and thus affecting(More)
Exosomes are secreted membrane vesicles that share structural and biochemical characteristics with intraluminal vesicles of multivesicular endosomes (MVEs). Exosomes could be involved in intercellular communication and in the pathogenesis of infectious and degenerative diseases. The molecular mechanisms of exosome biogenesis and secretion are, however,(More)
Accumulating evidence shows that several cell types have the capacity to secrete membrane proteins by incorporating them into exosomes, which are small lipid vesicles derived from the intralumenal membranes of multivesicular bodies (MVBs) of the endocytic pathway. Exosomes are expelled in the extracellular space upon fusion of the MVB with the plasma(More)
Dendritic cells constitutively secrete a population of small (50-90 nm diameter) Ag-presenting vesicles called exosomes. When sensitized with tumor antigenic peptides, dendritic cells produce exosomes, which stimulate anti-tumor immune responses and the rejection of established tumors in mice. Using a systematic proteomic approach, we establish the first(More)
Secretion of cytolytic granules content at the immunological synapse is a highly regulated process essential for lymphocyte cytotoxicity. This process requires the rapid transfer of perforin containing lytic granules to the target cell interface, followed by their docking and fusion with the plasma membrane. Defective cytotoxicity characterizes a(More)
Dendritic cells (DCs) are professional antigen presenting cells with the unique capacity to induce primary and secondary immune responses in vivo. Here, we show that DCs secrete antigen presenting vesicles, called exosomes, which express functional Major Histocompatibility Complex class I and class II, and T-cell costimulatory molecules. Tumor(More)