Tiny things matter — for instance, one amino acid can completely alter the architecture of the cell. Researchers have now investigated the structure and mechanics of the main component of the cytoskeleton of the cell: a protein known as actin. Actin is found in all living cells where it has a range of important functions — from muscle contraction to cell signalling and cell shape. This protein comes in two different varieties termed ‘isoforms’, which are known as gamma actin and beta actin.