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Disease Associated Variations in Glutathione Peroxidase‐1 Affect Its Subcellular Localization and Function
Author(s) -
Ekoue Dede,
Bera Soumen,
Weinberg Frank,
Fricano Kristine,
Mao Mao,
Bonini Marcelo,
Diamond Alan
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.759.6
Subject(s) - glutathione peroxidase , biology , mitochondrion , gpx1 , subcellular localization , microbiology and biotechnology , cytoplasm , oxidative stress , biochemistry , superoxide dismutase
Glutathione peroxidase 1 (GPx‐1) is a selenium containing protein implicated in the risk of several diseases, including cancer. Two common variations in the GPx‐1 gene which are associated with cancer risk are the Pro198Leu polymorphism and the number of repeated alanine codons at the 5'‐end of the gene. To elucidate the molecular consequences of these variations, the subcellular location of GPx‐1 was investigated by ectopically expressing these allelic variants in GPx‐1‐null MCF‐7 human breast cancer cells. A differential distribution of the protein between the cytoplasm and mitochondria was observed in cells expressing the Leu198 polymorphism and 7 alanine repeats (A7L), which partitioned to the cytoplasm more than the other alleles examined. To determine the consequences of these distributions, GPx‐1 variants were genetically targeted exclusively to the mitochondria and derivative cell lines were examined for changes in mitochondrial activity, molecular signaling and their response to oxidative stress. GPx‐1 A7L cells were significantly more resistant to tert‐butyl hydroperoxide ( t‐ BOOH) than the other cells. The Seahorse XF24 Analyzer was used to simultaneously determine relative oxygen consumption and extracellular acidification rates. Mitochondrial targeted A7L GPx‐1 resulted in increased oxidative phosphorylation compared to cells expressing other GPx‐1 isoforms. The results of these studies indicated that the GPx‐1 primary sequence affects localization and that both sequence and cellular location have a profound impact on cellular biology and may therefore be important in understanding how GPx‐1 impacts human diseases, including cancer.