title: Chemical chaperones and permissive temperatures alter localization of Gaucher disease associated glucocerebrosidase variants.
abstract: Point mutations in the lysosomal hydrolase, glucocerebrosidase (GC), can cause Gaucher disease, a common lysosomal storage disease. Several clinically important GC mutations impede folding in the endoplasmic reticulum (ER) and target these enzymes for ER-associated degradation (ERAD). The removal of these misfolded proteins decreases the lysosomal concentration of GC, which results in glucosylceramide accumulation. The most common GC variant, N370S, and other clinically relevant variants, G202R and L444P, exhibit different cellular localization patterns in patient-derived fibroblasts. We show that these distributions can be altered by manipulation of the ER folding environment, either by chemical chaperones or by temperature shifts. N370S, L444P, and G202R GC are destabilized in the neutral pH environment of the ER, rendering them prone to ERAD. Fibroblasts harboring the G202R and L444P GC mutations grown at 30 degrees C localize the mutant proteins to the lysosome, and this increases total GC activity. Both of these temperature-sensitive mutants appear to be stable at 37 degrees C once they are trafficked to the low pH environment of the lysosome. Chemical chaperones correct the ER instability and significant ER retention of G202R GC. N370S is also destabilized under ER simulating conditions, a deficiency that is corrected by chemical chaperone binding. These data clearly show manipulating the ER environment with chemical chaperones increases the lysosomal concentration of partially active GC variants and suggest that small molecules could be used to treat Gaucher disease.
authors.affiliation: Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Anu R
authors.initials: AR
authors.lastname: Sawkar
authors.forename: Martina
authors.initials: M
authors.lastname: Schmitz
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Zimmer
authors.forename: David
authors.initials: D
authors.lastname: Reczek
authors.forename: Tim
authors.initials: T
authors.lastname: Edmunds
authors.forename: William E
authors.initials: WE
authors.lastname: Balch
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Kelly
mesh_terms: D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005776:Gaucher Disease / Q000201:enzymology* / Q000235:genetics / Q000628:therapy; D014644:Genetic Variation; D005962:Glucosylceramidase / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism* / Q000627:therapeutic use; D011485:Protein Binding / Q000235:genetics; D013696:Temperature
chemical_list: D018832:Molecular Chaperones; D005962:Glucosylceramidase