They are tiny and hairy and sit on almost all of our cells. Of course we are talking about cilia, protein structures that are key to numerous functions of our body. However, if their assembly is incorrect or incomplete, patients are unable to hear and their kidneys would lose the ability to filtrate blood. Scientists at the Max Planck Institute (MPI) of Biochemistry in Munich-Martinsried, Germany, have now been able to elucidate a fundamental mechanism mediating the transport of new building blocks to the cilia. “The mechanism we investigated can explain how the cell provides new material for the cilia and how failures in this process lead to diseases like deafness“, says André Mourão, first author of the study.