MED4 and non-small cell lung carcinoma: Similar results were obtained for the interaction between MED12 (kinase) and MED8 (head), MED6 (head), MED1 (middle), MED4 (middle) or MED23 (tail) in NSCLC cells with repressed MED13L expression, indicating that MED13L is a vital linker protein between the core Mediator and the CDK8 kinase module (Figure 4C).