They solved the crystal structures of the luminal linker in three different pH conditions (corresponding to the pH in lysosomes, endosomes and in the extracellular milieu) to elucidate its role in the dual regulation of TRPML1 by luminal Ca2+ and pH, TRPML1 channel assembly and MLIV pathogenesis. This evidence concerns the gene MCOLN1 and mucolipidosis type IV.