YidC1 YidC2

Bacteria That Cause Tooth Decay Able To Survive Without Important Biochemical Pathway: "Brady's team surmised that two other molecules, called YidC1 and YidC2, might be acting as alternate routes for protein delivery in the absence of the SRP pathway. They tested their hypothesis and found that S. mutans could continue to function in non-stress conditions without the SRP and YidC1 genes, but not without the YidC2 and SRP simultaneously.
'The fact that the bacteria could survive without the SRP pathway was the most striking finding for scientists in the membrane protein insertion field,' said Ross E. Dalbey, Ph.D., a professor of chemistry at The Ohio State University. 'The big question now is discovering how these proteins are targeted in the absence of the SRP pathway, and I think that will be an important area of future research.' "

SRP

Bacteria That Cause Tooth Decay Able To Survive Without Important Biochemical Pathway: "The signal recognition particle, or SRP, pathway is a primary mechanism by which proteins are chaperoned from cellular assembly lines, where they are made, to the protective outer surface of the cells, where they are inserted. Without a steady infusion of proteins, the membrane weakens and the cell - in this case, a bacterium - becomes unable to protect itself from harsh environmental conditions. "

Scythe Balances Life And Death During Development

Scythe Balances Life And Death During Development: "A protein called Scythe determines which cells live and which die during the growth and development of the mammalian embryo.

Scythe plays a critical role during development of mammals by selectively regulating when and where specific cells either proliferate or undergo apoptosis, the process by which cells self-destruct. Understanding exactly how Scythe balances apoptosis with cell proliferation could provide significant insights into how organs develop in the growing embryo.

Previous work by other researchers suggests that the Scythe protein might work by regulating the folding and activity of the molecules that make up the signaling pathway that controls apoptosis. Scythe was also known to interact with another protein called Reaper to control development of the fruit fly. Therefore, the St. Jude team developed laboratory models lacking both copies of Scythe to study what happens in the gene's absence. The scientists discovered that major defects in lung development appeared late in the process of embryo development.

Cells from the Scythe-/- model responded to ionizing radiation and hydrogen peroxide by undergoing apoptosis like normal cells. However, these cells were more resistant to menadiaone and thapsigarin--two chemicals known to trigger apoptosis. But when the investigators put Scythe genes back into the cells, they became sensitive to these treatments and underwent apoptosis.

"These chemicals affect the movement of calcium inside a special structure where proteins are made," McKinnon said. "This showed that Scythe helps trigger apoptosis in specific circumstances. Further studies are currently underway to elucidate this process."
Part of the Scythe molecule resembles that of molecules known to be involved with protein destruction, according to Fabienne Desmots, the postdoctoral researcher in the Department of Genetics and Tumor Cell Biology who did much of the work on this project. This finding suggests that Scythe might help to regulate the signaling molecules that are involved in either apoptosis or cell proliferation."

p63

The Hospital for Sick Children - Release: "'We discovered that p63 is the major death-promoting protein for nerve cells during fetal and post-natal development,' said Dr. David Kaplan, the paper's senior author, senior scientist at SickKids, professor of Molecular Genetics, Medical Genetics & Microbiology at U of T, Canada Research Chair in Cancer and Neuroscience, and co-team leader on the NeuroScience Canada Brain Repair Program grant with Dr. Freda Miller of SickKids. 'Proteins such as p63 that regulate beneficial cell death processes during development may cause adverse affects later in life by making us more sensitive to injury and disease.'

While p63 is involved in determining which nerve cells die, the research team also suspects that it determines whether nerve cells die when injured or in neurological and neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases."

elF3

New Insights Into Protein Synthesis And Hepatitis C Infections: "Protein synthesis in mammalian cells begins with the loading of mRNA onto the small ribosome subunit, 40S, which is, in part, one of the responsibilities of the eIF3 complex. The eIF3 complex also interacts with other translation elements that bind at the start of the mRNA, prevents premature joining of the 40S and 60S ribosomal subunits, and helps assemble active ribosomes. Until now, the structural basis for eIF3's multiple activities has been unknown.

At a resolution of 30 angstroms, the cryo-EM reconstructions of Doudna and Nogales and their collaborators show eIF3 to be a particle consisting of five lobes - analogous to a head, and a pair of arms and legs. The study shows that the left arm of the eIF3 complex binds to the eukaryotic protein complex that recognizes the methylated guanosine cap at the 5’-end of the eukaryotic mRNAs (mRNA consists of a coding region sandwiched between a 5’-end and a 3’-end). By drawing the mRNA’s 5’-end cap through the ribosome entry site and towards the exit, eIF3 ensures the mRNA is properly positioned for its genetic code to be translated.

Acting like a molecular wrestler, eIF3 will also wrap its arms and legs around a structural element of RNA for the hepatitis C virus (HVC), known as the internal ribosome entry site (IRES), and pin it to the exit site of the 40S ribosome subunit. The IRES leaves through the left arm of the eIF3 complex at the same location where interaction with the human mRNA cap-binding complex takes place."

p53 Clumps and Pediatric Adrenocortical Cancer

Collapse Of p53 Into Clumps Might Be Linked To Cancer, According To St. Jude: "The mutation that causes clumps to form is associated only with the pediatric cancer adrenocortical carcinoma (cancer of the outer layer of the adrenal gland), suggesting a link between clump formation for mutant p53 in adrenal cells and the resulting cancer. Although the current finding only suggests a link between p53 clumps and adrenocortical carcinoma, mutations that disrupt various proteins have broader implications. The resulting aggregates, called amyloid fibrils, are also associated with diseases such as Alzheimer's and Parkinson's."

Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain

Overproducing Leptin Receptors In Fat Cells May Be Key To Halting Weight Gain: "When fat cells increase in size -- as they do during the development of obesity -- the cells progressively lose receptors for the hormone leptin, a powerful stimulus for fat burning. Leptin, a hormone produced by the body's fat cells and involved in the regulation of body weight, was first discovered in 1994. It was thought leptin itself would be a key to curing obesity in humans, but the hypothesis did not readily translate into weight loss in obese people. Using mouse models, UT Southwestern researchers have now shown that if enough receptors are present on the fat cells, it is impossible for the cells to store fat and obesity would be blocked."

Protein Kinase Cell Signaling Networks

Yale Scientists Decipher 'Wiring Pattern' Of Cell Signaling Networks: "Protein kinases act as regulator switches and modify their target proteins by adding a phosphate group to them. This process, called 'phosphorylation,' results in altered activity of the phosphorylated protein. It is estimated that 30% of all proteins are regulated by this process. "