ARHGEF6, also known as alpha-PIX or Cool-2, is a guanine nucleotide exchange factor belonging to the Dbl-related guanylate exchanger (GEF) family. It specifically activates Rho GTPases CDC42 and RAC1, playing a key role in biological processes such as cell migration, focal adhesion, and cytoskeletal rearrangement. It acts downstream of integrin-linked kinase (ILK) and parvin proteins, suggesting its involvement in integrin-mediated signaling pathways [1,3].

In genetic studies, Arhgef6-deficient mouse models recapitulated features of human congenital anomalies of the kidneys and urinary tract (CAKUT), indicating that deleterious variants in ARHGEF6 may cause dysregulation of integrin-parvin-RAC1/CDC42 signaling, leading to X-linked CAKUT [1]. In another study, knockdown of Arhgef6 in mice caused hair cell stereocilia deficits, progressive hair cell loss, and hearing loss, with the levels of active CDC42 and RAC1 dramatically decreased, suggesting that ARHGEF6 regulates stereocilia maintenance through RAC1/CDC42 [2].

In conclusion, ARHGEF6 is crucial for regulating cell-related processes such as migration, adhesion, and cytoskeletal rearrangement through activating CDC42 and RAC1. Studies using Arhgef6-deficient mouse models have revealed its role in diseases like CAKUT and hearing loss, enhancing our understanding of the molecular mechanisms underlying these conditions and potentially providing new insights for diagnosis and treatment.