Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.
Defects in MED17 are the cause of microcephaly postnatal progressive with seizures and brain atrophy (MCPHSBA) [MIM:613668]. It is a disorder characterized by postnatal progressive microcephaly and severe developmental retardation associated with cerebral and cerebellar atrophy. Infants manifest swallowing difficulties leading to failure to thrive, jitteriness, poor visual fixation, truncal arching, seizures. There is no acquisition of developmental milestones and patients suffer from marked spasticity and profound retardation. Progressive microcephaly becomes evident few months after birth.
Belongs to the Mediator complex subunit 17 family.
Phosphorylated upon DNA damage, probably by ATM or ATR.