Spatial proteomics reveals carboxysome adaptation and mitochondrial proteome in Paulinella chromatophora.

Spatial proteomics uncovers unique organelle adaptations and protein import mechanisms in Paulinella chromatophora, highlighting 16 nucleus-encoded proteins associated with chromatophore carboxysomes.

• Why it matters: Understanding organelle evolution and function in non-model organisms like P. chromatophora fills critical gaps in knowledge about primary endosymbiosis and organelle adaptation, which has implications for evolutionary biology and bioengineering.
• What they did: Using isotope tagging and differential centrifugation (LOPIT-DC), the study mapped subcellular protein localization, revealing persistent chromatophore transit peptides, absence of β-barrel proteins, and lineage-specific mitochondrial proteins.
• The result: Findings demonstrate conserved and novel features of organelles, including a potential O2-scavenging system in chromatophore carboxysomes, enabling insights into organelle evolution and functional specialization in this unique lineage.