Fig. 7: The various biological functions of the human Rix1 scaffolding complex.
From: Cryo-EM reveals the architecture of the PELP1-WDR18 molecular scaffold
The human Rix1 scaffolding complex is implicated in various biological functions in the cell nucleus including large subunit (60 S) ribosome assembly, heterochromatin maintenance, and steroid receptor coactivation of transcription. PELP1 is the central scaffold of the Rix1 complex and is likely primarily associated with, and functions within, this complex in the nucleus during its roles in ribosome assembly and heterochromatin maintenance. PELP1 facilitation/influence on ERα coactivation is likely a secondary or tertiary effect in the heterogenous and functionally diverse ERα signaling pathway. We hypothesize that PELP1 can influence ERα coactivation in transient/unique states, possibly when PELP1 is dissociated from the Rix1 complex either normally or during altered states of PELP1 proteostasis in the cell. This dissociation from the Rix1 complex may allow PELP1 to undergo conformational structural changes that form favorable LxxLL/PxxP motifs allowing for ERα co-regulation. Illustration created with BioRender.com.
