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Anti‐oxidative functions of C. elegans mechanosensory protein 6 (MEC‐6), a homolog for human PON1.
Author(s) -
Lee Elsa,
Schwarzer Christian,
Machen Terry E,
Forte Trudy M,
Forte John G
Publication year - 2006
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.20.5.lb22-a
Subject(s) - pon1 , paraoxonase , oxidative stress , wild type , oxidative phosphorylation , green fluorescent protein , microbiology and biotechnology , mutant , caenorhabditis elegans , biology , biochemistry , hela , chemistry , gene , in vitro , genotype
The mechanosensory protein 6 (MEC‐6) of C. elegans encodes a single‐pass membrane protein with sequence homology to the paraoxonase (PON) family of proteins, e.g., 25% identical and 45% similar to PON1 over a stretch of 377 amino acids in its carboxy terminus. The focus of this research was to identify the analogous functions of MEC‐6 to the PON family. We examined 1) enzymatic activity of recombinant MEC‐6 (rMEC‐6), 2) putative anti‐oxidative functions of MEC‐6 in HeLa cells and 3) role of mec‐6 in the protection of C. elegans from oxidative stress. We found rMEC‐6 was able to hydrolyze phenyl acetate and dihydrocouramin, two known substrates of PON in a Ca 2+ ‐dependent manner, indicating that MEC‐6 had PON‐like function as an arylesterase and a lactonase. To examine the role of MEC‐6 as an anti‐oxidant, we created a stable line of HeLa cells expressing MEC‐6. Using a redox‐sensitive green fluorescent protein (roGFP1) assay, we found that cells overexpressing MEC‐6 protein were afforded much better protection from exposure to exogenous oxidants compared to control cells. These data were equivalent to previously demonstrated anti‐oxidant capabilities of hPON2. To test the role mec‐6 in C. elegans animals, we looked at two different mutant mec‐6 alleles and their ability to cope with oxidative insult. Exposing young adult animals to 40 uM H 2 O 2 for 2 hours killed 80% of mec‐6 null animals compared to 40% loss in wildtype. Thus, the survival rate was decreased in mec‐6 null animals compared to wildtype animals. These studies reveal a role for MEC‐6 protein providing protection against oxidative stress. Support by DK10141.