Mediator complex subunit 23 (MED23)

Mediator complex subunit 23 (MED23) is a large subunit of the Mediator multiprotein coactivator complex that acts as a critical regulator of transcription by RNA polymerase II in eukaryotes[1][4]. MED23 is part of the Tail module of the Mediator complex, and serves as a direct interface for multiple sequence-specific transcription factors—such as the MAPK-responsive factor Elk-1—thereby integrating extracellular and intracellular signaling information into gene-specific transcriptional responses[1][2][7][8]. The protein has a highly structured, arch-shaped conformation made up of multiple HEAT repeats organized into α-solenoids, facilitating broad protein–protein interactions, including with splicing factors like hnRNP L and epigenetic regulators such as the E3 ubiquitin ligase RNF20/40. Through these interactions, MED23 orchestrates processes ranging from histone modifications (notably, histone H2B mono-ubiquitination) to alternative mRNA splicing, connecting transcriptional activation with chromatin state and RNA metabolism[3][5][8]. Loss or aberrant function of MED23 impacts cell proliferation and differentiation, and aberrant upregulation is associated with tumorigenesis and cancer progression, particularly in lung tissue[3]. There are currently no approved therapeutic agents directly targeting MED23, but it is recognized as a functional and structurally druggable intersection in key gene regulation pathways.

Other names

MED23ARC130CRSP3DRIP130KIAA1216SUR2CRSP complex subunit 3hSur-2CRSP130CRSP133MRT18Activator-recruited cofactor 130 kDa componentCofactor required for Sp1 transcriptional activation subunit 3Protein sur-2 homologTranscriptional coactivator CRSP130Vitamin D3 receptor-interacting protein complex 130 kDa component

Not applicable; no clinically used drugs are directly targeting MED23, but it is a critical interaction point for transcription factor-mediated gene activation and epigenetic modulation