Diversification and functional expansion of archaeal T4F machineries.

Archaeal T4F machineries exhibit extensive diversity and structural innovation, with many organisms harboring multiple systems and a broad functional repertoire.

• Why it matters: Understanding the diversity and functional expansion of archaeal T4F systems is crucial for revealing how archaea adapt and interact with their environment, filling gaps in knowledge about their secretion mechanisms.
• What they did: The study used novel MacSyFinder2 models to identify and classify archaeal T4F systems across genomes, combined with structure-based phylogenetic analysis and genome-wide screening for signal peptidase III cleavage sites, revealing widespread substrate-binding proteins.
• The result: Findings suggest that substrate-binding proteins with SPIII cleavage sites functionalize T4F machineries for substrate scavenging, indicating an expanded functional role for archaeal T4F systems beyond their traditional functions.