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

Spatial proteomics uncovers unique protein targeting and adaptations in chromatophores and mitochondria of Paulinella chromatophora, including a permanent chromatophore transit peptide and lineage-specific proteins.

• Why it matters: Understanding organelle evolution and function in non-model organisms like P. chromatophora fills gaps in knowledge about primary endosymbiosis and organelle adaptation, which has implications for cell biology and evolutionary studies.
• What they did: Using isotope tagging and differential centrifugation-based spatial proteomics, the study generated a subcellular protein atlas, analyzed chromatophore-targeted proteins, and identified nucleus-encoded proteins associated with chromatophore carboxysomes and mitochondria.
• The result: Findings reveal a persistent chromatophore transit peptide, support vesicle-mediated protein import, and show lineage-specific mitochondrial proteins, advancing understanding of organelle evolution and adaptation in P. chromatophora.