When a bacterial cell divides, the cell membrane and cell envelope have to pinch together in the middle of the cell to separate it into two daughter cells. A ring of proteins called the divisome constricts, cleaving the cell in two. The protein FtsZ is a crucial component of this ring and many FtsZ subunits join together in a chain forming long filaments. These FtsZ filaments are anchored to the membrane by another protein, FtsA, so that the membrane also constricts when the FtsZ ring closes.
Recent exciting advances in electron cryo-microscopy (cryo-EM) have allowed scientists to find very detailed structures of some proteins. Still, determining the structure of many proteins remains too difficult for cryo-EM, as the images are too noisy to use for structure determination. Lori Passmore and Chris Russo from the LMB’s Structural Studies Division have designed new specimen support grids, made of pure gold, that improve the microscope image quality.
Cells contain specialised membrane-bound compartments called organelles, which are vital to the cell as they allow it to separate different biochemical reactions that otherwise might interfere with each other. To function correctly, these intracellular compartments need to recruit proteins from the cytoplasm, and since every organelle has a specific role, each one needs a particular set of proteins.
Dyneins are a family of motor proteins that move along microtubules powered by chemical energy from ATP. Andrew Carter and his group in the LMB’s Structural Studies Division have solved the structure of a dynein protein bound to a chemical that mimics the shape of ATP, and have shown for the first time how the dynein can ‘walk’ along the microtubule.
Dynein proteins carry various important cargos to different parts of the cell, and are crucial to correct cell function.
Life on Earth depends on catalysis. Chemical transformations essential for cellular function are too sluggish to happen spontaneously at ambient temperatures and pressures, thus nature has developed myriad catalysts (enzymes) that accelerate the many key reactions necessary for life.
It is well known that all animals have an internal circadian clock that responds to daily environmental changes of light and darkness, to inform the body to rest and sleep, or wake and be active. As well as a master clock, found in the part of the brain called the suprachiasmatic nucleus (SCN), other areas in the brain have now been shown to contain local clocks, but how these operate in conjunction with the SCN in regulating sleep-wake behaviour has been unknown.
Inside our cells are many small transport vesicles that act as carriers to move proteins and lipids around the cell. To maintain cell function, these vesicles have to deliver their cargo to exactly the right destination. New research by Mie Wong from Sean Munro’s group in the LMB’s Cell Biology Division has shown that when specific vesicles arrive at their correct site, they are captured and tethered by long golgin proteins, ensuring that the cargo is delivered to the right place.
An unexpected finding from Julian Sale’s group in the LMB’s PNAC Division has revealed that a specialised histone protein called H3.3 is needed for packaging UV-damaged DNA during replication. Use of this histone may act as a flag to help the cell find and repair the damage once replication has been completed, potentially reducing the chance of harmful mutations.
Every time a cell divides, the double-stranded DNA needs to be copied with the DNA strands separated in a replication fork.
Research from the LMB’s PNAC Division has revealed a new mechanism that cells use to fight infection. Jerry Tam and other members of Leo James’s group have discovered that the protein complement C3, which covalently labels viruses and bacteria in the bloodstream, activates a potent immune response upon cell invasion.
Molecular biologists chemically modify proteins to label them for easy identification.
New research from Madan Babu’s group in the LMB’s Structural Studies Division, in collaboration with Toby Gibson from the European Molecular Biology Laboratory in Heidelberg, has shown that the targeted movement of mRNA molecules to allow proteins to be synthesised in specific locations has important implications in cell signalling and development.