Structural framework for the assembly of the human tRNA ligase complex.

Cryo-EM reveals the atomic structure of the human tRNA ligase complex, showing how non-catalytic subunits assemble to facilitate tRNA splicing.

• Why it matters: Understanding the molecular architecture of this complex is crucial because it plays a key role in tRNA biogenesis, a fundamental process for cellular function, yet its non-catalytic components are poorly characterized.
• What they did: The study used cryo-electron microscopy to determine the structure of the complex, revealing interactions among CGI-99, DDX1, FAM98B, Ashwin, and RTCB, and identifying distinct assemblies involving FAM98A and FAM98C.
• The result: These findings clarify how the complex is assembled and suggest specialized functions for different subcomplexes, advancing knowledge of tRNA processing and potential broader roles in cell biology.