RRC ID 36779
著者 Kamada Y, Kusakabe T, Sugimoto Y.
タイトル Amyloidogenic lysozymes accumulate in the endoplasmic reticulum accompanied by the augmentation of ER stress signals.
ジャーナル Biochim Biophys Acta
Abstract BACKGROUND:Naturally occurring single mutants, I56T, F57I, W64R and D67H of lysozyme in human, have been known to form abnormal protein aggregates (amyloid fibrils) and to accumulate in several organs, including the liver, spleen and kidney, resulting in familial systemic amyloidosis. These human pathogenic lysozyme variants are considered to raise subtle conformational changes compared to the wild type.
METHODS:Here we examined the effects of the aberrant mutant lysozymes I56T, F57I, W64R and D67H, each of which possesses a point mutation in its molecule, on a cultured human cell line, HEK293, in which the genes were individually integrated and overexpressed.
RESULTS:Western blot analyses showed lesser amounts of these variant proteins in the medium compared to the wild type, but they were abundant in the cell pellets, indicating that the modified lysozyme proteins were scarcely secreted into the medium but were retained in the cells. Immunocytochemistry revealed that these proteins resided in restricted regions which were stained by an endoplasmic reticulum (ER) marker. Moreover, the overexpression of the mutant lysozymes were accompanied by marked increases in XBP-1s and GRP78/BiP, which are downstream agents of the IRE1α signaling pathway responding to the unfolded protein response (UPR) upon ER stress. RNAi for the mutant lysozymes' expression greatly suppressed the increases of these agents.
CONCLUSIONS AND GENERAL SIGNIFICANCE:Our results suggest that the accumulation of pathogenic lysozymes in the ER caused ER stress and the UPR response mainly via the IRE1α pathway.
巻・号 1850(6)
ページ 1107-19
公開日 2015-6-1
DOI 10.1016/j.bbagen.2015.01.018
PII S0304-4165(15)00038-0
PMID 25659958
MeSH Amyloidosis, Familial / enzymology* Amyloidosis, Familial / genetics DNA-Binding Proteins / metabolism Endoplasmic Reticulum / enzymology* Endoplasmic Reticulum Chaperone BiP Endoplasmic Reticulum Stress* Endoribonucleases / metabolism Gene Expression Regulation, Enzymologic Genotype HEK293 Cells Heat-Shock Proteins / metabolism Humans Models, Molecular Muramidase / chemistry Muramidase / genetics Muramidase / metabolism* Mutation Phenotype Protein Conformation Protein Serine-Threonine Kinases / metabolism RNA Interference RNA, Messenger / metabolism Regulatory Factor X Transcription Factors Signal Transduction* Structure-Activity Relationship Transcription Factors / metabolism Transfection Unfolded Protein Response X-Box Binding Protein 1
IF 3.411
引用数 4
WOS 分野 BIOPHYSICS BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
ヒト・動物細胞 293(RCB1637)