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  • Sequestosome1/p62 protects mouse embryonic fibroblasts against low-dose methylercury-induced cytotoxicity and is involved in clearance of ubiquitinated proteins.

Sequestosome1/p62 protects mouse embryonic fibroblasts against low-dose methylercury-induced cytotoxicity and is involved in clearance of ubiquitinated proteins.

Scientific reports (2017-12-03)
Yasukazu Takanezawa, Ryosuke Nakamura, Ryohei Harada, Yuka Sone, Shimpei Uraguchi, Masako Kiyono
ABSTRACT

Methylmercury (MeHg) is a widely distributed environmental pollutant that causes a series of cytotoxic effects. However, molecular mechanisms underlying MeHg toxicity are not fully understood. Here, we report that sequestosome1/p62 protects mouse embryonic fibroblasts (MEFs) against low-dose MeHg cytotoxicity via clearance of MeHg-induced ubiquitinated proteins. p62 mRNA and protein expression in MEFs were temporally induced by MeHg exposure p62-deficient MEFs exhibited higher sensitivity to MeHg exposure compared to their wild-type (WT) counterparts. An earlier and higher level of accumulation of ubiquitinated proteins was detected in p62-deficient cells compared with WT MEFs. Confocal microscopy revealed that p62 and ubiquitinated proteins co-localized in the perinuclear region of MEFs following MeHg treatment. Further analysis of MEFs revealed that ubiquitinated proteins co-localized with LC3-positive puncta upon co-treatment with MeHg and chloroquine, an autophagy inhibitor. In contrast, there was minimal co-localization in p62-deficient MEFs. The present study, for the first time, examined the expression and distribution of p62 and ubiquitinated proteins in cells exposed to low-dose MeHg. Our findings suggest that p62 is crucial for cytoprotection against MeHg-induced toxicity and is required for MeHg-induced ubiquitinated protein clearance.

MATERIALS
Product Number
Brand
Product Description

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Anti-Lamin A/C Antibody, clone 14, clone 14, Upstate®, from mouse
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Anti-LC3B antibody produced in rabbit, ~1 mg/mL, affinity isolated antibody, buffered aqueous solution
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Dulbecco′s Modified Eagle′s Medium - high glucose, With 4500 mg/L glucose, L-glutamine, and sodium bicarbonate, without sodium pyruvate, liquid, sterile-filtered, suitable for cell culture