The CAB39 (Calcium Binding Protein 39) antibody is a research tool targeting the CAB39 protein, a key component of the LKB1/STRAD signaling complex. CAB39. also known as MO25. acts as a scaffolding protein that stabilizes interactions between the tumor suppressor kinase LKB1 and its co-activator STRAD. This complex regulates cellular energy metabolism, polarity, and proliferation via AMPK and other downstream kinases. CAB39 exists in two isoforms, CAB39α and CAB39β, with distinct tissue expression patterns. Dysregulation of CAB39 is implicated in cancer progression, metabolic disorders, and neurological diseases. CAB39 antibodies, including monoclonal and polyclonal variants, are widely used in techniques like Western blotting, immunohistochemistry, and immunofluorescence to study protein expression, localization, and interaction networks. Their specificity is often validated through knockdown/knockout controls. Research utilizing CAB39 antibodies has revealed its dual roles as both oncogene and tumor suppressor, depending on cellular context and isoform expression. These antibodies are critical for elucidating CAB39's involvement in mTOR signaling, autophagy regulation, and therapeutic resistance, making them valuable in both basic research and translational studies targeting metabolic and neoplastic diseases.