CAP2 (cyclase associated actin cytoskeleton regulatory protein 2) is a multifunctional protein that primarily regulates actin polymerization dynamics and cellular signaling pathways 1. The protein contains distinct functional domains, including N-terminal and C-terminal regions that serve different roles - the N-terminal domain is involved in adenylyl cyclase regulation while the C-terminal domain affects cellular morphology and actin dynamics 2. CAP2 plays a critical role in actin filament organization, as demonstrated by studies showing that CAP2 mutations impair actin repolymerization kinetics in patient fibroblasts 3. Beyond cytoskeletal regulation, CAP2 functions in cellular signaling and immune responses, with bacterial homologs serving as immune priming factors through ubiquitin transferase-like mechanisms 4. Clinically, CAP2 mutations are associated with dilated cardiomyopathy, where a homozygous splice site mutation causes protein instability and cardiac dysfunction including supraventricular tachycardia 3. The protein also shows disease relevance in cancer, where upregulated CAP2 promotes gastric cancer metastasis by mediating tumor-macrophage interactions and activating pro-metastatic signaling pathways 5. These findings establish CAP2 as an essential regulator of both structural and signaling processes in mammalian cells.