Gene repertoire expansion and cis-regulatory diversification shaped 26S proteasome evolution within a proteostasis-centered network

The 26S proteasome plays a crucial role in maintaining proteostasis across eukaryotes. While its core functionality is conserved, the evolution of its subunits and regulatory feedback mechanisms remains unclear. To unravel this, researchers performed a comprehensive study on plant 26S proteasomes. They discovered that proteasome gene repertoires expanded independently in different plant lineages.

Paralogs exhibited alterations in post-translational modification sites and transcriptional responses to environmental changes. Promoter analysis unveiled significant diversification of proteasome-associated cis-regulatory elements. These findings led to the identification of telomere repeat-binding proteins as new transcription regulators of proteasome genes in Arabidopsis thaliana, interacting with the PRCE motif.

Evolutionary rate comparisons unveiled a conserved network of proteasome-associated components, all linked through shared cis-elements that regulate cellular proteostasis. This study reveals that plant 26S proteasome is governed by a regulatory framework that integrates conserved mechanisms, unique innovations, and stress-responsive adaptations, emphasizing the central role of this complex in cellular health.