Their findings, published in the June issue of Plos Biology, counter the prevailing belief that HIV and other retroviruses can only leave and enter cells by virus-specific mechanisms.
“It appears that cells make HIV and other retroviruses by a naturally occurring export mechanism,” says Stephen Gould, Ph.D., Professor of Biological Chemistry at Johns Hopkins. Cells normally export certain membrane-bound molecules to the outside world by means of small sacs known as exosomes. By studying human T-cells under a microscope, Gould, Yi Fang, Ning Wu, and other members of his team discovered what’s needed to qualify proteins for exosomal travel.
“Surprisingly, all that’s needed for a protein to get out of the cell in exosomes are the ability to clump together and attach to the cell’s membrane,” Gould says.
In one experiment, Gould and his team added chemicals to normal human cells that force nearby proteins together into a clump, and this was enough to get them sent out of the cell in exosomes. If they added a tether to force naturally-clumping proteins inside the cell to the membrane, the proteins met a similar exosomal deportation fate.
The major HIV protein ‘Gag’ has both of these properties that cells sense in selecting exosomal cargoes. When the researchers removed the tethers or clumping signals from Gag it could no longer get out of the cell. However, if they were replaced with synthetic membrane anchors and clumping domains Gag regained its ability to get out of cells in exosomes.
Gould speculates that cells may have initially developed exosomes as a quality control mechanism to get rid of clumped proteins, which are generally broken and useless. However, just as retroviruses exploit other cell processes for their own ends, it now appears they rely on exosomes to get out of infected cells and infect fresh cells. As such, drugs that interfere with exosome formation might be one way to inhibit HIV infections.
“Viruses like HIV use pathways we barely recognize, much less understand,” Gould says. “Our paper highlights the importance of studying their basic biochemistry and cell biology, which can yield a better understanding of normal human biology as well as identify new avenues in the fight against human disease.”
Nick Zagorski | EurekAlert!
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy