Fibroblasts of WT and type 2 GD patients were obtained from Cornell Cel Repositories (Camden, NJ, USA). Antibodies targeted for GFP (sc-9996), His-tag (sc-57598), and GAPDH (sc-25778) were all purchased from Santa Cruz Biotechnology (Dallas, TX USA). PCDGF antibody (40—3400) was procured from Invitrogen (Waltham, MA, USA). ERp57 antibody (G117) was procured from Cell Signaling Technology (Danvers, MA, USA). All fluorescence-labeled secondary antibodies used in these experiments were purchased from Jackson Immuno Research Laboratories (West Grove, PA, USA). The substrate 4-Methylumbelliferyl β-D-glucopyranoside (4-MUG, M3633) was acquired from Sigma-Aldrich (Natick, MA, USA). The dye, LysoTracker Red DND99 (L7528), and both resins, Pierce High-Capacity Endotoxin Removal Resin (2,162,373.3) and HisPur™ Ni–NTA Resin (88,221), were all purchased from Thermo Fisher Scientific (Bridgewater, NJ, USA). The fluorescent stain, DAPI (H-1200), was acquired from VECTOR Laborato-ries (Burlingame, CA, USA). As delineated previously, the purified recombinant His-tag-PGRN protein was collected from HEK293T stable cell lines [30 (link)]. Fetal bovine serum (FBS, 16,000-044) as well as the Dulbecco’s modified Eagle’s medium (DMEM; 11,965-118) were both acquired from Gibco-BRL (Waltham, MA, USA).