Principles of ribosome-associated protein quality control during the synthesis of CFTR.

Ribosome-associated protein quality control (RQC) is triggered by inherent synthesis challenges of transmembrane segments in CFTR, with 20% of nascent chains arresting during translation.

• Why it matters: Understanding how RQC responds to transmembrane protein synthesis is crucial because defects in this process can lead to diseases like cystic fibrosis, yet the mechanisms remain unclear.
• What they did: The study used reporter assays in HEK293 cells to analyze CFTR translation, testing various interventions affecting folding, membrane insertion, and translation kinetics, including codon usage and ER targeting factors.
• The result: Findings reveal that RQC activation is primarily due to intrinsic difficulties in transmembrane segment synthesis, not folding defects or translation regulation, highlighting a novel physiological role for RQC in managing elongation arrest during transmembrane protein synthesis.