Every cell in the body normally has its fixed place as part of a tissue structure. Except for a few cell types, such as blood or immune cells. But cancer cells also cross established boundaries, grow into the surrounding tissue and multiply. And they can detach from the cell structure and spread via the blood or lymphatic vessels to other areas of the body, where they attach to new cells and form metastases.

The changes that cancer cells undergo to metastasize are not yet fully understood. Rho (Ras-homologous) GTPases apparently play an important role. These proteins process signals within cells and regulate, among other things, growth, differentiation into the genetically predetermined cell type and cell migration.

Rho GTPases are molecular switches that switch between an active and an inactive state by binding to the phosphate compounds GTP and GDP. GTP corresponds to the ‘on’ position of the switch and starts the molecular biological processes, while GDP corresponds to the ‘off’ position and stops them.

Phages are viruses that attack bacteria by injecting their DNA, then usurping bacterial machinery to reproduce. Eventually, they make so many copies of themselves that the bacteria burst. By looking at this process in a unique type of virus called a jumbo phage, scientists hope to learn how to make new antibiotics that can address the growing crisis of resistance.

The jumbo phage has more than four times the DNA of an average phage. It uses this genetic material to create a restricted space inside bacteria where it can copy its DNA while surrounded by a protective shield made of protein.

Researchers at UC San Francisco have discovered that the shield works via a set of “secret handshakes.” They allow only a specific set of useful proteins to pass through.