Protein degradation in a LAMP-2-deficient B-lymphoblastoid cell line from a patient with Danon disease

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1862

Article

Sanchez-Lanzas, Raul^1,2  Alvarez-Castelao, Beatriz^1,2,6  Bermejo, Teresa^1,2  Ayuso, Teresa³  Tunon, Teresa^4,5  Castano, Jose G.^1,2 

[1] UAM CSIC, Inst Invest Biomed Alberto Sols, Dept Bioquim, Madrid 28029, Spain

[2] UAM, Ctr Invest Biomed Red Enfermedades Neurodegenrat, Fac Med, Madrid 28029, Spain

[3] Complejo Hosp Navarra, Dept Neurol, Pamplona 31008, Spain

[4] Complejo Hosp Navarra, Anat Patol, Pamplona 31008, Spain

[5] Inst Invest Biomed Navarra IdisNa, Biobanco Tejidos Neurol, Ctr Invest Biomed, Pamplona 31008, Spain

[6] Max Planck Inst Brain Res, Synapt Plast, D-60438 Frankfurt, Germany

关键词: Danon disease;    LAMP-2;    Autophagy;    Ubiquitin proteasome;    Chaperone-mediated autophagy;    Alpha-synuclein;    IkappaB;    Rcan1;    glyceraldehyde-3-phosphate dehydrogenase;   

DOI  :  10.1016/j.bbadis.2016.04.014

来源: Elsevier

【 摘 要 】

Danon disease, a condition characterized by cardiomyopathy, myopathy, and intellectual disability, is caused by mutations in the LAMP-2 gene. Lamp-2A protein, generated by alternative splicing from the Lamp-2 pre-mRNA, is reported to be the lysosomal membrane receptor essential for the chaperone-mediated autophagic pathway (CMA) aimed to selective protein targeting and translocation into the lysosomal lumen for degradation. To study the relevance of Lamp-2 in protein degradation, a lymphoblastoid cell line was obtained by EBV transformation of B-cells from a Danon patient. The derived cell line showed no significant expression of Lamp-2 protein. The steady-state mRNA and protein levels of alpha-synuclein, IKB alpha, Rcan1, and glyceraldehyde-3-phosphate dehydrogenase, four proteins reported to be selective substrates of the CMA pathway, were similar in control and Lamp-2-deficient cells. Inhibition of protein synthesis showed that the half-life of alpha-synuclein, IKB alpha, and Rcan1 was similar in control and Lamp-2-deficient cells, and its degradation prevented by proteasome inhibitors. Both in control and Lamp-2-deficient cells, induction of CMA and macroautophagy by serum and aminoacid star-vation of cells for 8 h produced a similar decrease in IKB alpha and Rcan1 protein levels and was prevented by the addition of lysosome and autophagy inhibitors. In conclusion, the results presented here showed that Lamp-2 deficiency in human lymphoblastoid cells did not modify the steady-state levels or the degradation of several protein substrates reported as selective substrates of the CMA pathway. (C) 2016 Elsevier B.V. All rights reserved.

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