Human sleeping sickness — African trypanosomiasis — is caused by the protozoan parasite
Vanhamme et al. localized SRA to the lysosome and identified the human-specific serum protein apoL-I — an apolipoprotein associated with high density lipoprotein — as the human trypanolytic factor. The amino-terminal α-helix of SRA bound to a carboxy-terminal α-helix of apoL-I, and disabled its lytic function. ApoL-I observed to enter parasite cells via the endocytic pathway and co-localized with SRA in the lysosome, where the two proteins subsequently interacted.
Blocking the SAR-apoL-I interaction may help to prevent or treat the disease. "This works opens the way for the characterization of peptides that would be useful for both therapy of sleeping sickness due to