The tube is part of the 26S proteasome, an enzyme that acts as the cell’s protein garbage disposal. As described by researchers from the Technion-Israel Institute of Technology and the University of Texas Health Science Center at San Antonio, the tube is a concentric stack of rings wrapped in molecular motors that speed the proteins toward the proteasome’s slicing and dicing core.
“The life of all proteins in our cells ends within the proteasome chamber of doom,” Technion author Michael Glickman explained. He suggested that the newly-described pathway “should be of interest in applications for diseases in which cells are unable to process degraded or misfolded proteins,” including Alzheimer’s and Parkinson’s disease, some cancers, and age-related conditions such as cataract disease.
The study, published online in June in the journal Nature Structural and Molecular Biology, will help researchers understand the basic biology of the proteasome and “its intrinsic essential function in a myriad of cellular pathways,” said Allen Taylor, who has studied proteasome function extensively as director of the Laboratory for Nutrition and Vision Research at Tufts University.
The 26S proteasome degrades proteins that are marked for destruction with a ubiquitin protein “tag.” The proteasome itself consists of two major structures: a large core structure where the proteins are degraded, and a smaller structure that serves as a kind of entryway where the tagged protein makes its first contact with the proteasome and is unfolded for its journey into the core. The tube described by Glickman and colleagues is part of the smaller structure, and serves a chute between the first contact site and the core.
The researchers used atomic force microscopy to visualize the extremely tiny tube, which Glickman described as two molecular “donuts” stacked on top of each other. The donut holes through which proteins pass is only two nanometers in diameter. (For comparison, the period at the end of this sentence is one million times wider than a nanometer.)
The tube is ringed by a group of energy-producing enzymes called ATPases, which act a motor to drive proteins through the tube. “One may see the entire machine as an external engine wrapping around an inner molecular stent for protein translocation, all situated atop the molecular shredder into which the proteins are fed,” Glickman explained.
It’s a natural design that engineers working on synthetic nanomachines might hope to copy in their own creations, he noted.
The Technion-Israel Institute of Technology is Israel's leading science and technology university. Home to the country’s winners of the Nobel Prize in science, it commands a worldwide reputation for its pioneering work in nanotechnology, computer science, biotechnology, water-resource management, materials engineering, aerospace and medicine. The majority of the founders and managers of Israel's high-tech companies are alumni. Based in New York City, the American Technion Society (ATS) is the leading American organization supporting higher education in Israel, with 22 offices around the country.
Kevin Hattori | Newswise Science News
Study identifies RNA molecule that shields breast cancer stem cells from immune system
23.05.2017 | Princeton University
“Pregnant” Housefly Males Demonstrate the Evolution of Sex Determination
23.05.2017 | Universität Zürich
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Earth Sciences
23.05.2017 | Life Sciences
23.05.2017 | Physics and Astronomy