title: The role of ceroid lipofuscinosis neuronal protein 5 (CLN5) in endosomal sorting.
abstract: Mutations in the gene encoding CLN5 are the cause of Finnish variant late infantile Neuronal Ceroid Lipofuscinosis (NCL), and the gene encoding CLN5 is 1 of 10 genes (encoding CLN1 to CLN9 and cathepsin D) whose germ line mutations result in a group of recessive disorders of childhood. Although CLN5 localizes to the lysosomal compartment, its function remains unknown. We have uncovered an interaction between CLN5 and sortilin, the lysosomal sorting receptor. However, CLN5, unlike prosaposin, does not require sortilin to localize to the lysosomal compartment. We demonstrate that in CLN5-depleted HeLa cells, the lysosomal sorting receptors sortilin and cation-independent mannose 6-phosphate receptor (CI-MPR) are degraded in lysosomes due to a defect in recruitment of the retromer (an endosome-to-Golgi compartment trafficking component). In addition, we show that the retromer recruitment machinery is also affected by CLN5 depletion, as we found less loaded Rab7, which is required to recruit retromer. Taken together, our results support a role for CLN5 in controlling the itinerary of the lysosomal sorting receptors by regulating retromer recruitment at the endosome.
authors.affiliation: Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montreal, Canada.
authors.forename: Aline
authors.initials: A
authors.lastname: Mamo
authors.forename: Felix
authors.initials: F
authors.lastname: Jules
authors.forename: Karine
authors.initials: K
authors.lastname: Dumaresq-Doiron
authors.forename: Santiago
authors.initials: S
authors.lastname: Costantino
authors.forename: Stephane
authors.initials: S
authors.lastname: Lefrancois
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D006056:Golgi Apparatus; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D009472:Neuronal Ceroid-Lipofuscinoses / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D017527:Receptor, IGF Type 2 / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism; D000099183:Sortilin
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D017527:Receptor, IGF Type 2; D033921:Vesicular Transport Proteins; D000099183:Sortilin; C034304:cation-dependent mannose-6-phosphate receptor