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Differential subcellular localization of endogenous and transfected soluble epoxide hydrolase in mammalian cells: evidence for isozyme variants
Author(s) -
Mullen Robert T,
Trelease Richard N,
Duerk Heike,
Arand Michael,
Hammock Bruce D,
Oesch Franz,
Grant David F
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00142-8
Subject(s) - epoxide hydrolase , epoxide hydrolase 2 , peroxisome , biochemistry , cytosol , hydrolase , microsomal epoxide hydrolase , biology , enzyme , chemistry , gene , microsome
Endogenous, constitutive soluble epoxide hydrolase in mice 3T3 cells was localized via immunofluorescence microscopy exclusively in peroxisomes, whereas transiently expressed mouse soluble epoxide hydrolase (from clofibrate‐treated liver) accumulated only in the cytosol of 3T3 and HeLa cells. When the C‐terminal Ile of mouse soluble epoxide hydrolase was mutated to generate a prototypic putative type 1 PTS (‐SKI to ‐SKL), the enzyme targeted to peroxisomes. The possibility that soluble epoxide hydrolase‐SKI was sorted slowly to peroxiosmes from the cytosol was examined by stably expressing rat soluble epoxide hydrolase‐SKI appended to the green fluorescent protein. Green fluorescent protein soluble epoxide hydrolase‐SKI was strictly cytosolic, indicating that ‐SKI was not a temporally inefficient putative type 1 PTS. Import of soluble epoxide hydrolase‐SKI into peroxisomes in plant cells revealed that the context of ‐SKI on soluble epoxide hydrolase was targeting permissible. These results show that the C‐terminal ‐SKI is a non‐functional putative type 1 PTS on soluble epoxide hydrolase and suggest the existence of distinct cytosolic and peroxisomal targeting variants of soluble epoxide hydrolase in mouse and rat.