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LNX (Ligand of Numb-protein X) interacts with RhoC, both of which regulate AP-1-mediated transcriptional activation

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Abstract

LNX (Ligand of Numb-protein X) was originally isolated as a binding partner to the cell-fate Determinant Numb during development, and then identified to act as a RING finger-type E3 ubiquitin ligase for the ubiquitylation and degradation of Numb. LNX contains 4 PDZ domains which are proved to play a central role in organizing diverse cell signaling assemblies. A yeast two-hybrid screening was used to identify LNX as a potential binding partner for RhoC. RhoC, a member of the Ras family of small GTPases, promotes reorganization of the actin cytoskeleton and regulation of cell shape, attachment, and motility. The interaction between LNX and RhoC in mammalian cells was identified by co-immunoprecipitation assays, and the efficient binding required the first PDZ domain of LNX. LNX and RhoC were further colocalized with each other in mammalian cells, in which RhoC changed its sublocalization from cytoplasm to nucleus when co-transferred with LNX. Furthermore, co-expression of RhoC reduced the transcriptional activity of AP-1, which was up-regulated by over-expression of LNX alone. These results suggest that LNX and RhoC might be part of a larger protein complex that would have important functions in signaling transduction about regulating the transcriptional activities of AP-1.

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Acknowledgments

This work was supported by the National Science Foundation of China (No. 30671145).

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Authors and Affiliations

  1. State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 200433, Shanghai, People’s Republic of China

    Dan Zheng, Yaqiong Sun, Shaohua Gu, Chaoneng Ji, Wei Zhao, Yi Xie & Yumin Mao

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  1. Dan Zheng
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  2. Yaqiong Sun
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  3. Shaohua Gu
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  4. Chaoneng Ji
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  5. Wei Zhao
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  6. Yi Xie
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  7. Yumin Mao
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Correspondence to Yumin Mao.

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Zheng, D., Sun, Y., Gu, S. et al. LNX (Ligand of Numb-protein X) interacts with RhoC, both of which regulate AP-1-mediated transcriptional activation. Mol Biol Rep 37, 2431–2437 (2010). https://doi.org/10.1007/s11033-009-9754-5

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  • DOI: https://doi.org/10.1007/s11033-009-9754-5

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