Eaf6

Eaf6 is a protein that, in many eukaryotes, functions as a component of the SAGA transcriptional coactivator complex. In the budding yeast Saccharomyces cerevisiae, Eaf6 (Eaf6p) is one of several non-enzymatic subunits that help assemble and stabilize the complex, which regulates gene expression by modulating chromatin structure and recruiting transcription machinery to promoters. Eaf6 itself is not known to possess catalytic activity; rather, it is thought to contribute to the integrity of SAGA and to facilitate interactions between other subunits involved in histone modification and transcription initiation.

Localization studies place Eaf6 primarily in the nucleus, where SAGA operates on chromatin. Biochemical and genetic analyses indicate that Eaf6 interacts with other SAGA components and participates in the regulated activities of the complex, though its exact molecular duties are not fully defined. The protein is predicted to be a structural or adaptor element within the complex, helping to maintain proper assembly and function rather than driving enzymatic reactions.

Eaf6 is conserved in a range of fungal species and show homologs in other eukaryotes, suggesting an evolutionarily preserved role in transcriptional regulation. Across species, however, the depth of functional conservation can vary, and the precise contribution of Eaf6 to SAGA-mediated transcription may differ accordingly. In model organisms, deletion or disruption of EAF6 often results in modest or context-dependent transcriptional changes, with more pronounced effects under certain stresses or genetic backgrounds, underscoring its supportive rather than central role.

Overall, Eaf6 is recognized as a conserved, non-enzymatic subunit of the SAGA complex, contributing to complex stability and regulation of transcription through chromatin modification, while remaining a subject of ongoing research to fully delineate its specific interactions and functions.