BAIAP2L1 (also known as IRTKS) is a multifunctional adaptor protein that plays critical roles in cytoskeletal organization and cellular processes. The protein contains a BAR domain that enables dimerization and liquid-liquid phase separation, facilitating various cellular functions 12. BAIAP2L1 is essential for microvillus biogenesis, appearing as puncta at cell surfaces that mark future sites of protrusion growth and directing actin bundle formation 3. The protein regulates actin cytoskeleton dynamics and airway smooth muscle contraction, with deletion affecting muscle contractility in response to specific stimuli 4. In cancer contexts, BAIAP2L1 demonstrates oncogenic properties through multiple mechanisms. It can form fusion proteins with receptor tyrosine kinases, particularly FGFR3-BAIAP2L1, which drives constitutive kinase activation and transformation through BAR domain-mediated dimerization 15. The protein is upregulated in various cancers including ovarian and papillary thyroid carcinomas, promoting cell proliferation and serving as a potential biomarker 67. Additionally, BAIAP2L1 contributes to heterochromatin formation and maintenance through phase separation, helping prevent cellular senescence by stabilizing HP1α and maintaining genome stability 2.