# The Mediator Complex: From Transcriptional Regulation to Disease Pathogenesis

## TL;DR

This review explores how specific parts of the Mediator complex contribute to diseases like cancer and metabolic disorders, offering insights into potential therapies.

## Contribution

The paper provides a subunit-specific synthesis of Mediator biology and its role in disease pathogenesis, including a comprehensive table of disease associations.

## Key findings

- Individual Mediator subunits have distinct roles in human physiology and disease.
- Disruption of specific Mediator subunits contributes to cancer and developmental disorders.
- Mediator interacts with cohesin and architectural factors to regulate genome organization.

## Abstract

The Mediator complex is a central regulator of eukaryotic transcription, functioning as a dynamic molecular interface between gene-specific transcription factors and RNA polymerase II (Pol II). Although its overall architecture and general role in transcription have been extensively reviewed, accumulating genetic, genomic, and clinical evidence indicates that individual Mediator subunits make distinct and non-redundant contributions to human physiology and disease. In this review, we move beyond a generic description of Mediator function and present a subunit-resolved synthesis of Mediator biology with an emphasis on disease pathogenesis. A key feature of this review is a comprehensive table integrating disease associations and molecular functions of individual human Mediator subunits, enabling rapid assessment of functional specialization across the complex. We further discuss chromatin-based mechanisms of Mediator action, including cooperation with cohesin and architectural factors to regulate enhancer-promoter communication and higher-order genome organization. By organizing recent structural, mechanistic, and pathological findings into a unified framework, this review highlights how disruption of specific Mediator subunits contributes to cancer, developmental disorders, and metabolic disease, and outlines emerging opportunities for therapeutic intervention.