Search results for "multivesicular bodies"

Permeability changes of integrin-containing multivesicular structures triggered by picornavirus entry.

2014

Cellular uptake of clustered α2β1-integrin induces the formation of membrane compartments that subsequently mature into a multivesicular body (MVB). Enhanced internalization mediated by clustered integrins was observed upon infection by the picornavirus echovirus 1 (EVI). We elucidated the structural features of virus-induced MVBs (vMVBs) in comparison to antibody-induced control MVBs (mock infection) by means of high-pressure cryo fixation of cells followed by immuno electron tomography during early entry of the virus. Three-dimensional tomograms revealed a marked increase in the size and complexity of these vMVBs and the intraluminal vesicles (ILVs) at 2 and 3.5 hours post infection (p.i.…

Clustering-triggered endocytic pathway of α2β1 integrin

2012

Coxsackievirus A9 Infects Cells via Nonacidic Multivesicular Bodies

2014

ABSTRACT Coxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae . According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, the structures utilized by the virus for internalization and uncoating are less well understood. We show here, based on electron microscopy, that CVA9 is found in multivesicular structures 2 h postinfection (p.i.). A neutral red labeling assay revealed that uncoating occurs mainly around 2 h p.i., while double-stranded RNA is found in the cytoplasm after 3 h p.i. The biogenesis of multivesicu…

Mechanisms of RNA loading into exosomes

2015

AbstractUpon fusion of multivesicular bodies (MVBs) with the plasma membrane, intraluminal vesicles (ILVs) are released into the extracellular space as exosomes. Since the lipid composition of the exosomal membrane resembles that of raft microdomains, the inward budding process involves the raft-like region of the MVB limiting membrane. Although published research suggests that cellular RNAs may be selectively sorted into exosomes, the molecular mechanisms remain elusive. In this review, we suggest that there is a continuous interaction of cellular RNAs with the outer (cytoplasmic) surface of MVBs and that the selection for incorporation of these RNAs into ILVs is based on their affinity to…

EXOSOMES: CAN DOCTORS STILL IGNORE THEIR EXISTENCE?

2013

With this invited commentary we want to draw the attention of young medical doctors, the main readers of this journal, towards the existence and importance of a group of nanovesicles released by human cells: the exosomes. These vesicles are incontinently se-creted as a mean of cell-to-cell communication. They are involved in a number of physiol-ogic processes as well as in the pathogenesis of, virtually, all human diseases. They can be isolated from all biological fluids, like blood, urine, sweat, sperm, crevicular fluid, bile, etc., and their composition in terms of proteins, RNA and lipids is different in pathology that in physiologic conditions. It is therefore possible to predict that t…

Hsp60 from cancer cells can reach near and distant targets: A proposal for a multistage pathway

2011

Cancer cells have means to influence other cells in their vicinity and distant, and in this signal-delivering mechanisms the chaperonin Hsp60 plays a role, which is currently being recognized as potentially crucial for the growth and dissemination of at least certain types of tumors. In order to arrive at its destination, Hsp60, a typical resident of mitochondria in normal and tumor cells, leaves the organelle and reaches the blood. In the latter, Hsp60 can travel and arrive at targets situated far away from its origin. The details of the route followed by Hsp60 and their molecular mechanisms have not yet been fully elucidated. We investigated Hsp60 levels and secretion in normal and tumor …

Binding of RNA Aptamers to Membrane Lipid Rafts: Implications for Exosomal miRNAs Transfer from Cancer to Immune Cells

2020

Intraluminal vesicles (ILVs) are released into the extracellular space as exosomes after the fusion of multivesicular bodies (MVBs) with the plasma membrane. miRNAs are delivered to the raft-like region of MVB by RNA-binding proteins (RBPs). RNA loading into exosomes can be either through direct interaction between RNA and the raft-like region of the MVB membrane, or through interaction between an RBP&ndash

γ2-Adaptin is functioning in the late endosomal sorting pathway and interacts with ESCRT-I and -III subunits.

2010

Abstractγ2-Adaptin is a clathrin adaptor-related protein with unclear physiological function. Previous studies indicated that γ2-adaptin might act within the multivesicular body (MVB) protein-sorting pathway that is central to receptor down-regulation, lysosome biogenesis, and budding of enveloped viruses. Here, we have analyzed the effects of excess and deficit γ2-adaptin on exogenous and endogenous MVB cargoes and on the MVB machinery itself. Foreign cargoes, like retroviral Gags, are entrapped by overexpressed γ2-adaptin in detergent-insoluble polymers and blocked in budding. When viral budding involves MVB/endosomal structures, excess γ2-adaptin acts by accelerating lysosomal Gag destru…

Improving extracellular vesicles visualization: From static to motion

2020

AbstractIn the last decade, extracellular vesicles (EVs) have become a hot topic. The findings on EVs content and effects have made them a major field of interest in cancer research. EVs, are able to be internalized through integrins expressed in parental cells, in a tissue specific manner, as a key step of cancer progression and pre-metastatic niche formation. However, this specificity might lead to new opportunities in cancer treatment by using EVs as devices for drug delivery. For future applications of EVs in cancer, improved protocols and methods for EVs isolation and visualization are required. Our group has put efforts on developing a protocol able to track the EVs for in vivo intern…

Exosomes and other extracellular vesicles in neural cells and neurodegenerative diseases

2016

The function of human nervous system is critically dependent on proper interneuronal communication. Exosomes and other extracellular vesicles are emerging as a novel form of information exchange within the nervous system. Intraluminal vesicles within multivesicular bodies (MVBs) can be transported in neural cells anterogradely or retrogradely in order to be released into the extracellular space as exosomes. RNA loading into exosomes can be either via an interaction between RNA and the raft-like region of the MVB limiting membrane, or via an interaction between an RNA-binding protein-RNA complex with this raft-like region. Outflow of exosomes from neural cells and inflow of exosomes into neu…