ITSN2 (intersectin 2) is a multi-domain scaffold protein that serves as a critical adapter in clathrin-mediated endocytosis and cellular signaling pathways 1. The protein exists in two major splice isoforms: a short form containing EH domains, coiled-coil region, and five SH3 domains, and a longer form with additional DH, PH, and C2 domains that functions as a guanine nucleotide exchange factor for Rho-like GTPases 12. ITSN2 regulates endocytic processes by inhibiting transferrin internalization and colocalizing with endocytic machinery components like Eps15 1. The protein interacts with multiple signaling partners including Eps8, promoting its degradation through lysosomal pathways 3, and WIP in invadopodia formation during cancer cell invasion 4. ITSN2 demonstrates differential phosphorylation patterns compared to ITSN1, enabling specific recognition by SH2 domain-containing proteins including kinases and adaptor proteins 5. Clinically, ITSN2 mutations are associated with nephrotic syndrome, where it functions as a Cdc42 guanine nucleotide exchange factor in podocytes 2. The protein also plays roles in cellular senescence through ING1a-mediated upregulation and shows brain-specific expression patterns of certain splice variants 67.