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.
Insight on Research
Decade-long collaboration results in the first structure of the Fanconi anaemia core complex
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.
Fast, simple, accessible and affordable: The future of cryo-EM
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.
Structural insights into control of cell growth by nutrient availability
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.
How chromosomes are bound to be separated in cell division
When our cells divide, it is important that the pairs of chromosomes are correctly segregated, as errors in this process cause serious problems. For over a century, kinetochores have been recognised as the critical cellular structures responsible for attaching the chromosomes to the microtubules that direct this chromosomal segregation. However, how exactly kinetochores recognise the centromere, the central point that links the two halves of a chromosome, has been a long-standing question. David Barford’s group in the LMB’s Structural Studies Division and Stephen McLaughlin of the LMB’s Biophysics Facility, have now determined a structure of a kinetochore complex that suggests the answer to this question.
Mapping the human kidney
Chronic kidney disease affects more than 500 million patients worldwide, but there are no specific treatments that prevent disease progression. A lack of tissue availability has limited research into human kidney function and animal research hasn’t translated into treatments for human patients. Menna Clatworthy’s group, in the University of Cambridge Molecular Immunity Unit, which is housed within the LMB, has now generated the first atlas-scale dataset map of human kidney cells, which will begin to address this knowledge gap.