MYO9A encodes myosin IXA, an unconventional myosin motor protein that functions as a critical regulator of cellular architecture and signaling. The protein contains both motor and GTPase activating protein (GAP) domains, enabling it to regulate Rho GTPase activity while mediating actin-based cellular processes 1. MYO9A plays essential roles in epithelial cell junction assembly and polarity establishment, crosslinking and bundling actin filaments while deactivating RhoA to control cytoskeletal dynamics 1. In podocytes, MYO9A regulates cell attachment, migration, and maintains proper cytoskeletal architecture through its interaction with actin-calmodulin complexes 1. Disease relevance includes congenital myasthenic syndrome type 24, where MYO9A mutations impair neuromuscular junction function 2. Additionally, heterozygous loss-of-function mutations cause focal segmental glomerulosclerosis (FSGS) through podocyte dysfunction, as demonstrated in knock-in mice that develop proteinuria and kidney pathology 1. The protein also shows tumor suppressor properties in colorectal cancer, where downregulation disrupts epithelial polarity and contributes to worse prognosis 3. Clinically, MYO9A represents a potential therapeutic target for both kidney disease and cancer treatment.