Before import: N-terminal acetylation at the interface of plastid protein targeting and proteostasis.

N-terminal acetylation of plastid precursor proteins occurs before import, influencing their stability and import efficiency, with over 70% of precursors modified in vivo.

• Why it matters: Understanding how N-terminal processing affects plastid protein targeting is crucial for revealing mechanisms of organelle biogenesis and maintaining cellular proteostasis, which are vital for plant health and development.
• What they did: The study reviews current knowledge on N-terminal processing, including sequence features and NAT enzyme specificity, and presents evidence that precursor acetylation impacts stability, import, and quality control pathways.
• The result: Findings suggest that N-terminal acetylation plays a key role in precursor fate and organelle targeting, offering new insights into plastid biogenesis and potential avenues for improving plant proteostasis.