NUDCD3 (NudC domain containing 3) is a molecular chaperone essential for cytoplasmic dynein complex stability and function. It associates with both dynein-1 and dynein-2 complexes as a regulatory protein 1, and functions to stabilize dynein intermediate chain and prevent its proteasomal degradation 2. NUDCD3 is particularly critical for V(D)J recombination during T and B cell development; mutations cause severe combined immunodeficiency (SCID) or Omenn syndrome by impairing RAG-mediated recombination through pathologic sequestration of RAG1 in nucleoli 3. Beyond immune function, NUDCD3 regulates intermediate filament proteostasis by interacting with gigaxonin through its Kelch 3 motif, affecting vimentin filament morphology and degradation 4. NUDCD3's role in dynein-dependent processes extends to cilium assembly and protein localization to pericentriolar material. Gene aberrations involving NUDCD3, including novel NUDCD3-ROS1 fusions, have been identified in inflammatory myofibroblastic tumors 5. Overall, NUDCD3 functions as a chaperone supporting dynein stability and multiple cellular processes dependent on dynein motors and cytoskeletal organization.