RRC ID 11810
Author Dennemärker J, Lohmüller T, Müller S, Aguilar SV, Tobin DJ, Peters C, Reinheckel T.
Title Impaired turnover of autophagolysosomes in cathepsin L deficiency.
Journal Biol. Chem.
Abstract Some of the phenotypes of mice deficient for the lysosomal cysteine endopeptidase cathepsin L (Ctsl) are characterized by large dysmorphic vesicles in the cytoplasm. Specifically, the heart (dilative cardiomyopathy), the thyroid (impaired thyroglobulin processing) and keratinocytes (periodic hair loss and epidermal hyperproliferation) are affected. We hypothesized that the formation of aberrant vesicles is owing to defects in macroautophagy. Therefore, primary mouse embryonic fibroblasts (MEF), which were derived from Ctsl(-/-) animals crossed with mice transgenic for the autophagy marker GFP-LC3, were investigated. Ctsl(-/-) MEF show increased number and size of vesicular structures belonging to the 'acidic' cellular compartment and are also characterized by GFP-LC3. Induction of autophagy by nutrient starvation or rapamycin treatment showed no significant impairment of the initiation of autophagy, the formation of autophagosomes or autophagosome-lysosome fusion in Ctsl(-/-) MEF, but co-localization of GFP-LC3 and Lamp1 revealed unusually large autophagolysosomes filled with Lamp1. Furthermore, the soluble lysosomal enzyme cathepsin D was elevated in Ctsl(-/-) MEF. Thus, degradation of autophagolysosomal content is impaired in the absence of Ctsl. This could slow the turnover of autophagolysosomes and result in accumulation of the dysmorphic and 'acidic' vesicles that were previously described in the context of the pathological phenotypes of Ctsl(-/-) mice.
Volume 391(8)
Pages 913-22
Published 2010-8
DOI 10.1515/BC.2010.097
PMID 20536383
MeSH Animals Autophagy* Biomarkers / metabolism Cathepsin D / metabolism Cathepsin L / genetics Cathepsin L / physiology* Cells, Cultured Embryo, Mammalian Green Fluorescent Proteins / genetics Green Fluorescent Proteins / metabolism Lysosome-Associated Membrane Glycoproteins / metabolism Lysosomes / metabolism* Lysosomes / pathology Mice Mice, Knockout Mice, Transgenic Microscopy, Confocal Microscopy, Electron, Transmission Microscopy, Fluorescence Microtubule-Associated Proteins / genetics Microtubule-Associated Proteins / metabolism Organelle Size Phagosomes / metabolism* Phagosomes / pathology Recombinant Fusion Proteins / metabolism
IF 3.022
Times Cited 39
Mice GFP-LC3#53