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Covalent and Non‐covalent Interactions of Caveolin and Small Ubiquitin‐Related Modifier (SUMO)‐2/3
Author(s) -
Fuhs Stephen Rush,
Insel Paul A
Publication year - 2009
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.23.1_supplement.760.14
Subject(s) - sumo protein , caveolae , sumo enzymes , transfection , covalent bond , hek 293 cells , ubiquitin , immunoprecipitation , chemistry , microbiology and biotechnology , in vitro , biochemistry , biology , signal transduction , gene , organic chemistry
Caveolins (Cavs), critical protein components of caveolae, scaffold numerous signaling proteins. Cavs‐1 and ‐3 have a SUMOylation consensus motif and tandem SUMO Interacting Motifs (SIMs). We hypothesized that: 1) Cav is covalently SUMOylated and 2) interacts non‐covalently with SUMO. In vitro SUMOylation assays, transfection of HEK cells and immunoblots of cardiac myocyte lysates revealed that SUMO‐1 and SUMO‐2/3 covalently modify cav‐3 in vitro while only SUMO‐2/3 conjugates occur in cells. Cav‐3 co‐immunoprecipitated with the SUMO E2 (Ubc9) and E3 (PIASy). Co‐transfection of PIASy enhanced SUMOylation of cav‐3 and mutation of the consensus site Lys (K38R) reduced SUMOylation by 50%. To investigate non‐covalent interactions, we incubated rat cardiac myocyte lysates with agarose‐bound SUMO‐1 or SUMO‐2/3 and found a preference for SUMO‐2/3. Our findings implicate SUMOylation as a posttranslational modification that regulates the function of caveolin. We speculate that non‐covalent interaction may be important for its covalent modification by providing selectivity for SUMO‐2/3 vs. SUMO‐1. (supported by NIH grants and PhRMA Foundation Predoctoral Fellowship).