Bacteria that cause the bubonic plague avoid death in our bodies by injecting our cells with immune evasion proteins. Scientists have discovered a new way bacteria build and hold the syringes, according to research published in the journal Microbiology.
Some pathogenic bacteria have a complex injection device made of many proteins. This molecular syringe has to be attached across two membranes so that proteins can be passed from the bacterial cells into human cells.
Until now, scientists thought that the position of a key lipoprotein component of the syringe was determined by one or two specific amino acids as is true for all other bacterial lipoproteins. But research led by Dr Gregory Plano at the University of Miami Miller School of Medicine suggests that location is not always determined by these previously identified sorting signals.
“The YscJ lipoprotein in Yersinia pestis is an essential part of the injection device,” says Dr Plano. “It serves as a platform for the syringe to be built on and it is a major component of the structure that links the two bacterial cell membranes together. The sequence of YscJ suggests that it should be attached to the outer membrane, but it is actually attached to the inner membrane of the bacterial cell.” Instead of being controlled by a few key amino acids, the location of the YscJ lipoprotein is determined by the presence of a specific section of the protein.
Injection devices help pathogenic bacteria to survive in our bodies by injecting proteins that stop our immune cells from communicating and launching an attack. Some bacteria that are beneficial to plants and animals also use these devices to evade their hosts’ immune systems.
Understanding this mechanism tells us more about how Yersinia pestis causes plague. “We now want to find out why the YscJ protein uses this unusual mechanism instead of the traditional method used by other lipoproteins,” says Dr Plano.
Source: Society for General Microbiology
Related stories:
Atomic-resolution views suggest function of enzyme that regulates light-detecting signals in eye
An atomic-resolution view of an enzyme found only in the eye has given researchers at the University of Washington (UW) clues about how this enzyme, essential to vision, is activated. The enzyme, phosphodiesterase 6 (PDE6), is central to the way light entering the retina is converted into a cascade of signals to the brain.
Tracking Down the Cause of Mad Cow Disease
(PhysOrg.com) -- The cause of diseases such as BSE in cattle and Creutzfeld–Jakob disease in humans is a prion protein. This protein attaches to cell membranes by way of an anchor made of sugar and lipid components (a glycosylphosphatidylinositol, GPI) anchor. The anchoring of the prions seems to have a strong influence on the transformation of the normal form of the protein into its pathogenic form, which causes scrapie and mad cow disease.
First glimpse of a key DNA repair protein at work
Repairing breaks in the two strands of the DNA double helix is critical for avoiding cancer. In humans and other organisms, a molecular machine called the MRN complex is responsible for finding and signaling double-strand breaks (DSBs), then launching the error-free method of DNA repair called homologous recombination.
Models of Eel Cells Suggest Electrifying Possibilities
(PhysOrg.com) -- Engineers long have known that great ideas can be lifted from Mother Nature, but a new paper by researchers at Yale University and the National Institute of Standards and Technology takes it to a cellular level. Applying modern engineering design tools to one of the basic units of life, they argue that artificial cells could be built that not only replicate the electrical behavior of electric eel cells but in fact improve on them. Artificial versions of the eel’s electricity generating cells could be developed as a power source for medical implants and other tiny devices, they say.
Don't stress! Bacterial crisis command center revealed
A bacteria cell's 'crisis command centre' has been observed for the first time swinging into action to protect the cell from external stress and danger, according to new research out today (3 October) in
Science.
What HIV needs: Identification of human factors may yield novel therapeutic targets for HIV
The Salk Institute for Biological Studies and Burnham Institute for Medical Research today announced 295 host cell factors that are involved in human immunodeficiency virus (HIV) infection. The study, published in the Oct. 3 issue of
Cell, could lead to the development of a new class of HIV therapeutics aimed at disrupting the human-HIV interactions that lead to viral infection.
Groundbreaking discovery may lead to stronger antibiotics
The last decade has seen a dramatic decline in the effectiveness of antibiotics, resulting in a mounting public health crisis across the world. A new breakthrough by University of Virginia researchers provides physicians and patients a potential new approach toward the creation of less resistant and more effective antibiotics.
TB Bacterium Uses Its Sugar Coat To Sweeten Its Chances Of Living In Lungs
(PhysOrg.com) -- Common strains of tuberculosis-causing bacteria have hijacked the human body’s immune response to play tricks on cells in the lungs, scientists say.