ECHS1 interacts with STAT3 and negatively regulates STAT3 signaling

Signal transducer and activator of transcription 3 (STAT3) is a critical transcriptional factor in a variety of cellular processes, and is frequently over-activated in a range of human tumors. However, the processes that regulate STAT3 activation need to be further clarified. With a yeast two-hybrid screening, we identified enoyl-CoA hydratase short chain 1 (ECHS1) as a novel STAT3 binding protein. We further confirmed the interaction between STAT3 and ECHS1 by GST-pull down and co-immnunoprecipitation. Importantly, we found that ECHS1 specifically represses STAT3 activity and negatively regulates the expression of several target genes of STAT3 through inhibiting STAT3 phosphorylation. Therefore, our findings will provide new insights into the mechanism of STAT3 signaling regulation.