The primary aim of our work was to analyse the cellular consequences of the StrN471D mutation in the model organism D. discoideum. Mutant strumpellin variants are known to cause a severe and relatively pure motor form of HSP (SPG8 or Strümpell-Lorrain-Disease, OMIM #603563) (Behan and Maia, 1974; Salinas et al., 2008; Valdmanis et al., 2007). This evidence concerns the gene WASHC5 and hereditary spastic paraplegia.