The I-TASSER server is an online resource for automated protein structure prediction and structure-based function annotation. It uses multiple threading alignment approaches to identify structural templates from the PDB and constructs full-length structure models through iterative fragment assembly simulations. The server also derives functional insights by matching predicted structures with known proteins in function databases. Recent developments include new methods for atomic-level structure refinement, local structure quality estimation, and improved biological function annotations. These advancements aim to enhance the accuracy and utility of the I-TASSER server for high-resolution structure and function prediction. The server has been widely used and has participated in community-wide blind experiments, demonstrating significant advantages over other methods in protein structure and function prediction.The I-TASSER server is an online resource for automated protein structure prediction and structure-based function annotation. It uses multiple threading alignment approaches to identify structural templates from the PDB and constructs full-length structure models through iterative fragment assembly simulations. The server also derives functional insights by matching predicted structures with known proteins in function databases. Recent developments include new methods for atomic-level structure refinement, local structure quality estimation, and improved biological function annotations. These advancements aim to enhance the accuracy and utility of the I-TASSER server for high-resolution structure and function prediction. The server has been widely used and has participated in community-wide blind experiments, demonstrating significant advantages over other methods in protein structure and function prediction.