CAND1 (cullin-associated and neddylation-dissociated 1) is a critical assembly factor for SCF (SKP1-CUL1-F-box protein) E3 ubiquitin ligase complexes that functions as an F-box protein exchange factor 1. In its deneddylated state, CAND1 binds to CUL1-RBX1, promoting dissociation of SCF complexes and facilitating exchange of substrate-recognition F-box proteins, thereby coordinating the cellular repertoire of ubiquitin ligase complexes 1. Through conformational rocking and allosteric destabilization mechanisms, CAND1 recycles the limiting CUL1 subunit across ~70 different F-box proteins, enabling responsive assembly of distinct multiprotein complexes in response to substrate availability 1. Clinically, CAND1 dysregulation contributes to multiple pathologies. In nonalcoholic fatty liver disease (NAFLD), reduced hepatic CAND1 enhances Cullin1/FBXO42-mediated degradation of ACAA2, a key fatty acid oxidation enzyme, exacerbating lipid accumulation 2. In cardiac pathology, CAND1 overexpression protects against hypertrophy and heart failure by promoting calcineurin degradation 3, while enhancing cardiomyocyte proliferation and heart regeneration via FBXW11-mediated Mob1b degradation 4. In non-small cell lung cancer, high ASCC3 recruits CAND1 to stabilize STAT3, impairing interferon responses and promoting immunosuppression 5. These findings identify CAND1 as a central regulator of protein homeostasis with broad therapeutic potential across metabolic, cardiac, and oncologic diseases.