Proteolysis within the membrane: Rhomboids revealed

The rhomboids are a recently discovered family of serine proteases with the unusual property of cleaving proteins within their transmembrane domains. They are the most widely conserved polytopic membrane proteins discovered so far Although not much is known about the spectrum of their biological roles, it is already clear that rhomboids control events as diverse as growth factor signalling and mitochondrial membrane dynamics. As with other intramembrane proteases, the molecular details of how proteolysis can occur in a lipid bilayer remain mysterious.