Intermolecular disulfide bond formation in the NEMO dimer requires Cys54 and Cys347

Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
Biochemical and Biophysical Research Communications (Impact Factor: 2.3). 03/2008; 367(1):103-8. DOI: 10.1016/j.bbrc.2007.12.123
Source: PubMed


NEMO is an essential regulatory component of the IkappaB kinase (IKK) complex, which controls activation of the NF-kappaB signaling pathway. Herein, we show that NEMO exists as a disulfide-bonded dimer when isolated from several cell types and analyzed by SDS-polyacrylamide gel electrophoresis under non-reducing conditions. Treatment of cells with hydrogen peroxide (H(2)O(2)) induces further formation of NEMO dimers. Disulfide bond-mediated formation of NEMO dimers requires Cys54 and Cys347. The ability of these residues to form disulfide bonds is consistent with their location in a NEMO dimer structure that we generated by molecular modeling. We also show that pretreatment with H(2)O(2) decreases TNFalpha-induced IKK activity in NEMO-reconstituted cells, and that TNFalpha has a diminished ability to activate NF-kappaB DNA binding in cells reconstituted with NEMO mutant C54/347A. This study implicates NEMO as a target of redox regulation and presents the first structural model for the NEMO protein.

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Available from: Sheila Yong, Jul 25, 2015
    • "Contradictory findings on the influence of ROS on IKK have been reported. Some studies show that ROS activate IKK kinase complex, the core element of the NF-κB cascade, while others found that ROS may have an inhibitory effect on this kinase (Byun et al. 2002; Herscovitch et al. 2008). Moreover, catalytically active subunit of IKK is a site for S-nitrosylation by nitric oxide. "
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    • "Studies concerning ROS influence on NF-κB activity have shown that H 2 O 2 can act as an activator of IKKs or can inactivate these proteins, probably depending on the cell-type (Kamata et al., 2002; Korn et al., 2001). According to some results, H 2 O 2 can be a factor that potentiates dimerization of IKKγ/NEMO by inducing the formation of disulfide bonds between Cys54 and Cys347 (Herscovitch et al., 2008). Although the authors showed that H 2 O 2 could modulate the NEMO monomer vs. dimer ratio, implicating that NEMO was positively regulated by ROS, it is most likely that H 2 O 2 inhibits IKK activation by directly affecting IKKβ. "
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    • "At the dimerization interface, the hydrophobic portions of these residues pack against each other with their hydrophilic portions facing outwards (Figure 2D). It has been shown that NEMO forms intermolecular disulfide bonds through C54 and C347 (Herscovitch et al., 2008). C347 is within the longer CC2-LZ construct (residues 251-350), which may stabilize dimerization via the intermolecular disulfide bond. "
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