Insight on Research

The first structure of a domesticated viral-like capsid provides a basis for understanding a novel means of neuronal communication The neuronal gene Arc plays important roles in neural plasticity, learning and memory-related molecular processes and has been shown to mediate intercellular RNA transfer by forming viral-like capsids. John Briggs’ group has now solved the first […]

By combining fluorescence microscopy and electron tomography, Wanda Kukulski’s lab in Cell Biology Division has visualised protein structures that bridge contact sites between the endoplasmic reticulum and plasma membrane in yeast, in their native environment i.e. within the cell.

Cells tightly control the levels of ‘housekeeping’ proteins to maintain smooth operation of basic life processes. The most common way cells accomplish this task is feedback control of transcription to turn on or turn off genes in response to perceived need of their protein products.

Our DNA contains all of the information required to tell a cell what it needs to do, but it is constantly being damaged. This damage can cause severe problems, making repair processes hugely important. One common type of DNA damage, known as crosslinking, involves links forming inappropriately between two nucleotide letters. Although the specific repair pathway that fixes DNA crosslinks, and the complex at the heart of it, have been known about for decades, a full mechanistic understanding has been missing. Lori Passmore’s group, in the LMB’s Structural Studies Division, has now revealed the structure of the complex at the heart of this repair pathway for the first time.

Is it possible to improve imaging of purified biological specimens in electron cryo-microscopy (cryo-EM) while also reducing its cost? The latest proof-of-principle paper from Chris Russo’s group says yes, and indicates that the answer lies in reducing the electron energy in the cryo-EM from the current standard of 300 or 200 kiloelectron volts (keV) to 100 keV. Recent measurements of radiation damage to biological specimens by high-energy electrons have shown that at lower energies there is an increased amount of information available per unit damage. The authors of the paper foresee that future cryo-microscopes designed for ultimate single-particle resolution will be designed to maximise this information. This will then make true atomic resolution (~1 Å) more accessible and affordable.

Control of cell division is crucially important, as unregulated cell division is a hallmark of cancer. mTORC1 protein kinase is an ancient enzyme complex and master regulator of growth and metabolism that integrates signals relating to nutrient availability, energy, and growth factors. Activation of mTORC1 is driven by proteins called Rags that sense nutrient abundance. However, some cancer-causing mutations make Rag proteins active even in the absence of nutrients and drive cells to divide when they shouldn’t. Roger Williams’ group, in the LMB’s PNAC Division, has now shown how active Rags bind to mTORC1 and how a cancer-associated mutation can make a Rag protein continuously active.