The Med1 Subunit of Transcriptional Mediator Plays a Central Role in Regulating CCAAT/enhancer-binding Protein-beta-driven Transcription in Response to Interferon-gamma
Overview
Authors
Affiliations
Transcription factor CCAAT/enhancer-binding protein (C/EBP)-beta is crucial for regulating transcription of genes involved in a number of diverse cellular processes, including those involved in some cytokine-induced responses. However, the mechanisms that contribute to its diverse transcriptional activity are not yet fully understood. To gain an understanding into its mechanisms of action, we took a proteomic approach and identified cellular proteins that associate with C/EBP-beta in an interferon (IFN)-gamma-dependent manner. Transcriptional mediator (Mediator) is a multisubunit protein complex that regulates signal-induced cellular gene transcription from enhancer-bound transcription factor(s). Here, we report that the Med1 subunit of the Mediator as a C/EBP-beta-interacting protein. Using gene knock-out cells and mutational and RNA interference approaches, we show that Med1 is critical for IFN-induced expression of certain genes. Med1 associates with C/EBP-beta through a domain located between amino acids 125 and 155 of its N terminus. We also show that the MAPK, ERK1/2, and an ERK phosphorylation site within regulatory domain 2, more specifically the Thr(189) residue, of C/EBP-beta are essential for it to bind to Med1. Last, an ERK-regulated site in Med1 protein is also essential for up-regulating IFN-induced transcription although not critical for binding to C/EBP-beta.
Characterization of Med1 LxxLL Motif Involved in Fumonisin Biosynthesis.
Zhou Z, Liu J, Zhang J, Yan H, Yi T, Shim W Toxins (Basel). 2023; 15(11).
PMID: 37999515 PMC: 10675092. DOI: 10.3390/toxins15110652.
MED1 Deficiency in Macrophages Accelerates Intimal Hyperplasia via ROS Generation and Inflammation.
Zhang Y, Fu Y, Zhang C, Jia L, Yao N, Lin Y Oxid Med Cell Longev. 2021; 2021:3010577.
PMID: 34853629 PMC: 8629658. DOI: 10.1155/2021/3010577.
Ito K, Schneeberger M, Gerber A, Jishage M, Marchildon F, Maganti A Genes Dev. 2021; 35(9-10):729-748.
PMID: 33888560 PMC: 8091968. DOI: 10.1101/gad.346791.120.
Evidence for additive and synergistic action of mammalian enhancers during cell fate determination.
Choi J, Lysakovskaia K, Stik G, Demel C, Soding J, Tian T Elife. 2021; 10.
PMID: 33770473 PMC: 8004103. DOI: 10.7554/eLife.65381.
CDK8-Novel Therapeutic Opportunities.
Menzl I, Witalisz-Siepracka A, Sexl V Pharmaceuticals (Basel). 2019; 12(2).
PMID: 31248103 PMC: 6630639. DOI: 10.3390/ph12020092.