TNF-{alpha} Induction of CXCL10 in Endothelial Cells Requires Protein Arginine Methyltransferase 5 (PRMT5)-mediated NF-{kappa}B p65 Methylation [Cell Biology]

April 21st, 2014 by Harris, D. P., Bandyopadhyay, S., Maxwell, T. J., Willard, B., DiCorleto, P. E. .

The chemokine CXCL10/IP-10 facilitates recruitment of Th1-type leukocytes to inflammatory sites. In this study, we show that the arginine methyltransferase PRMT5 is critical for CXCL10 transcription in TNF-α-activated human endothelial cells (EC). We found that depletion of PRMT5 results in significantly reduced levels of CXCL10 mRNA, demonstrating a positive role for PRMT5 in CXCL10 induction. Chromatin immunoprecipitation experiments revealed the presence of symmetrical dimethylarginine (SDMA) modification catalyzed by PRMT5 associated with the CXCL10 promoter in response to TNF-α. However, SDMA-modified proteins were not detected at the promoter in the absence of PRMT5, indicating that PRMT5 is essential for methylation to occur. Further, NF-κB p65, a critical driver of TNF-α-mediated CXCL10 induction, was determined to be methylated at arginine residues. Crucially, RNAi-mediated depletion of PRMT5 prevented p65 methylation, and mass spectrometric analysis identified five dimethylated arginine residues in p65, four of which are uncharacterized in the literature. Expression of Arg-to-Lys point mutants of p65 demonstrated that both Arg30 and Arg35 must be dimethylated to achieve full CXCL10 expression. In conclusion, we have identified previously uncharacterized p65 post-translational modifications critical for CXCL10 induction.
  • Posted in Journal of Biological Chemistry, Publications
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