Identification of lysosomal Npc1-binding proteins: Cathepsin D activity is regulated by NPC1
Por:
J. MACIAS-VIDAL, M. GUERRERO-HERNANDEZ, J. ESTANYOL, C. AGUADO, E. KNECHT, M. COLL and O. BACHS
Publicada:
1 ene 2016
Resumen:
Niemann-Pick type C (NPC) disease is an inherited lysosomal storage disorder, characterized by severe neurodegeneration. It is mostly produced by mutations in the NPC1 gene, encoding for a protein of the late endosomes/lysosomes membrane, involved in cholesterol metabolism. However, the specific role of this protein in NPC disease still remains unknown. We aimed to identify Npc1-binding proteins in order to define new putative NPC1 lysosomal functions. By affinity chromatography using an Npc1 peptide (amino acids 1032-1066 of loop I), as bait, we fished 31 lysosomal proteins subsequently identified by LC-MS/MS. Most of them were involved in proteolysis and lipid catabolism and included the protease cathepsin D. Cathepsin D and NPC1 interaction was validated by immunoprecipitation and the functional relevance of this interaction was studied. We found that fibroblasts from NPC patients with low levels of NPC1 protein have high amounts of procathepsin D but reduced quantities of the mature protein, thus showing a diminished cathepsin D activity. The increase of NPC1 protein levels in NPC cells by treatment with the proteasome inhibitor bortezomib, induced an elevation of cathepsin D activity. All these results suggest a new lysosomal function of NPC1 as a regulator of cathepsin D processing and activity.
Filiaciones:
J. MACIAS-VIDAL:
Hosp Clin Barcelona, Serv Bioquim & Genet Mol, Seccio Errors Congenits Metab IBC, Barcelona, Spain
CIBER Enfermedades Raras CIBERER, Madrid, Spain
Inst Invest Biomed August Pi & Sunyer IDIBAPS, Barcelona, Spain
M. GUERRERO-HERNANDEZ:
Univ Barcelona, Dept Cell Biol Immunol & Neurosci, E-08036 Barcelona, Spain
J. ESTANYOL:
Univ Barcelona, Prote Unit, Ctr Cient, E-08036 Barcelona, Spain
Univ Barcelona, Prote Unit, Ctr Tecnol, E-08036 Barcelona, Spain
:
CIBER Enfermedades Raras CIBERER, Madrid, Spain
Ctr Invest Principe Felipe, Lab Cellular Biol, Valencia, Spain
:
CIBER Enfermedades Raras CIBERER, Madrid, Spain
Ctr Invest Principe Felipe, Lab Cellular Biol, Valencia, Spain
M. COLL:
Hosp Clin Barcelona, Serv Bioquim & Genet Mol, Seccio Errors Congenits Metab IBC, Barcelona, Spain
CIBER Enfermedades Raras CIBERER, Madrid, Spain
Inst Invest Biomed August Pi & Sunyer IDIBAPS, Barcelona, Spain
O. BACHS:
Inst Invest Biomed August Pi & Sunyer IDIBAPS, Barcelona, Spain
Univ Barcelona, Dept Cell Biol Immunol & Neurosci, E-08036 Barcelona, Spain
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