CDR2 (cerebellar degeneration related protein 2) is an onconeural antigen that functions as a dynein adaptor protein involved in endoplasmic reticulum (ER) organization 1. The protein is recruited by the integral ER membrane protein kinectin (KTN1) and, along with its paralog CDR2L, regulates ER sheet organization through dynein-mediated transport 1. CDR2 contains a dynein-binding CC1 box motif that is essential for its function in promoting centrosome-proximal clustering of ER sheets and preventing KTN1-dependent ER sheet stacking 1. In human brain tissue, CDR2 shows distinct cellular distribution compared to CDR2L, localizing primarily to vascular smooth muscle cells and cells lining the ventricular system, while CDR2L is found mainly in Purkinje cells and brainstem neurons 2. CDR2 and CDR2L serve as major targets of anti-Yo autoantibodies in paraneoplastic cerebellar degeneration, a cancer-related autoimmune disorder affecting cerebellar Purkinje cells 3. These onconeural antigens are expressed in both tumor cells and neurons, where they associate with ribosomes and play roles in transcription regulation and calcium homeostasis 3. CDR2 expression is significantly downregulated in Kawasaki disease, suggesting potential involvement in inflammatory vascular conditions 4.