Premium
Glycan binding protein galectin‐3 negatively regulates UT‐A1 urea transport activity by impairing protein membrane expression
Author(s) -
Li Xuechen,
Yang Baoxue,
Fröhlich Otto,
Hughey Rebecca P,
Chen Guangping
Publication year - 2013
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.27.1_supplement.1210.20
Subject(s) - galectin , biotinylation , chemistry , lipid raft , western blot , microbiology and biotechnology , immunoprecipitation , membrane protein , xenopus , biochemistry , cell , biology , membrane , gene
Galectins, a group of small lectin‐like proteins that bind â‐galactose‐enriched glycoconjugates, play many important roles in membrane protein regulation. By using a panel of GST‐conjugated galectin proteins (galectin‐1, 3, 4, 7, 8, and 9), we performed GST pulldown assays and found galectin‐3 could directly bind to urea transporter UT‐A1 from kidney inner medulla (IM). Northern blot analysis shows galectin‐3 highly expressed in IM, less in OM, and very low in cortex. Cell surface biotinylation shows galectin‐3 cell membrane expression in HEK293 cells. By sucrose density ultracentrifugation, we found that galectin‐3 is localized in lipid raft subdomains. Functional study by co‐injection of galectin‐3 with UT‐A1 cRNAs in Xenopus oocytes shows that galectin‐3 causes a reduction of UT‐A1 urea transport activity. To explore the possible mechanism of galectin‐3 downregulation of UT‐A1, we did cell surface biotinylation and found that overexpression of galectin‐3 in UT‐A1 HEK392 cell reduces UT‐A1 membrane expression. Our study suggests that association with galectin‐3 may represent a novel mechanism for UT‐A1 regulation.