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Mol. Cells 2010; 30(6): 527-532

Published online December 31, 2010

https://doi.org/10.1007/s10059-010-0155-3

© The Korean Society for Molecular and Cellular Biology

Regulation of IkappaB Kinase by GβL through Recruitment of the Protein Phosphatases

Dong-Joo You1, You Lim Kim1, Cho Rong Park1, Dong-Kyu Kim1, Jeonghun Yeom2, Cheolju Lee2, Curie Ahn3, Jae Young Seong1, and Jong-Ik Hwang1,*

1Graduate School of Medicine, Laboratory of G Protein Coupled Receptors, Korea University, Seoul 136-705, Korea, 2Life Sciences Division, Korea Institute of Science and Technology, Seoul 136-791, Korea, 3Transplantation Research Institute, Cancer Research Institute, Seoul National University, Seoul 110-799, Korea

Correspondence to : *Correspondence: hjibio@korea.ac.kr

Received: June 15, 2010; Revised: September 13, 2010; Accepted: September 17, 2010

Abstract

G protein β-like (GβL) is a member of WD repeat-con-taining family which are involved in various intracellular signaling events. In our previous report, we demon-strated that GβL regulates TNFα-stimulated NF-κB signaling by interacting with and inhibiting phosphorylation of IκB kinase. However, GβL itself does not seem to regulate IKK directly, because it contains no functional domains except WD domains. Here, using immunoprecipitation and proteomic analyses, we identified protein phosphatase 4 as a new binding partner of GβL. We also found that GβL interacts with PP2A and PP6, other members of the same phosphatase family. By interacting with protein phosphatases, which do not directly bind to IKKβ, GβL mediates the association of phosphatases with IKKβ. Overexpression of protein phosphatases inhibited TNFκ-induced acti-vation of NF-κB signaling, which is an effect similar to that of GβL overexpression. Down-regulation of GβL by small interfering RNA diminished the inhibitory effect of phosphatases, resulting in restoration of NF-κB signaling. Thus, we propose that GβL functions as a negative regulator of NF-κB signaling by recruiting pro-tein phosphatases to the IKK complex.

Keywords GβL, IκB kinase, NF-κB, phosphorylation, protein phosphatases

Article

Research Article

Mol. Cells 2010; 30(6): 527-532

Published online December 31, 2010 https://doi.org/10.1007/s10059-010-0155-3

Copyright © The Korean Society for Molecular and Cellular Biology.

Regulation of IkappaB Kinase by GβL through Recruitment of the Protein Phosphatases

Dong-Joo You1, You Lim Kim1, Cho Rong Park1, Dong-Kyu Kim1, Jeonghun Yeom2, Cheolju Lee2, Curie Ahn3, Jae Young Seong1, and Jong-Ik Hwang1,*

1Graduate School of Medicine, Laboratory of G Protein Coupled Receptors, Korea University, Seoul 136-705, Korea, 2Life Sciences Division, Korea Institute of Science and Technology, Seoul 136-791, Korea, 3Transplantation Research Institute, Cancer Research Institute, Seoul National University, Seoul 110-799, Korea

Correspondence to:*Correspondence: hjibio@korea.ac.kr

Received: June 15, 2010; Revised: September 13, 2010; Accepted: September 17, 2010

Abstract

G protein β-like (GβL) is a member of WD repeat-con-taining family which are involved in various intracellular signaling events. In our previous report, we demon-strated that GβL regulates TNFα-stimulated NF-κB signaling by interacting with and inhibiting phosphorylation of IκB kinase. However, GβL itself does not seem to regulate IKK directly, because it contains no functional domains except WD domains. Here, using immunoprecipitation and proteomic analyses, we identified protein phosphatase 4 as a new binding partner of GβL. We also found that GβL interacts with PP2A and PP6, other members of the same phosphatase family. By interacting with protein phosphatases, which do not directly bind to IKKβ, GβL mediates the association of phosphatases with IKKβ. Overexpression of protein phosphatases inhibited TNFκ-induced acti-vation of NF-κB signaling, which is an effect similar to that of GβL overexpression. Down-regulation of GβL by small interfering RNA diminished the inhibitory effect of phosphatases, resulting in restoration of NF-κB signaling. Thus, we propose that GβL functions as a negative regulator of NF-κB signaling by recruiting pro-tein phosphatases to the IKK complex.

Keywords: GβL, IκB kinase, NF-κB, phosphorylation, protein phosphatases

Mol. Cells
Sep 30, 2022 Vol.45 No.9, pp. 603~672
COVER PICTURE
The Target of Rapamycin Complex (TORC) is a central regulatory hub in eukaryotes, which is well conserved in diverse plant species, including tomato (Solanum lycopersicum). Inhibition of TORC genes (SlTOR, SlLST8, and SlRAPTOR) by VIGS (virus-induced gene silencing) results in early fruit ripening in tomato. The red/ orange tomatoes are early-ripened TORC-silenced fruits, while the green tomato is a control fruit. Top, left, control fruit (TRV2-myc); top, right, TRV2-SlLST8; bottom, left, TRV2-SlTOR; bottom, right, TRV2-SlRAPTOR(Choi et al., pp. 660-672).

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