Gelsolin (GSN) is a highly conserved actin-binding protein widely expressed across eukaryotes, functioning as a key regulator of the actin cytoskeleton. It modulates actin filament assembly and disassembly through calcium-dependent severing, capping, and nucleation activities, thereby governing cellular processes like motility, shape change, cytokinesis, and vesicular trafficking. GSN exists in two isoforms: cytoplasmic GSN (regulating intracellular actin dynamics) and plasma GSN (a secreted form involved in extracellular actin scavenging and inflammation modulation). Dysregulation of GSN is associated with multiple pathologies, including neurodegenerative diseases (e.g., Alzheimer’s), cancer metastasis, cardiovascular disorders, and inflammatory conditions. Its role in maintaining cytoskeletal homeostasis and extracellular matrix balance makes it a significant molecule in both physiological and pathological contexts.Besides,CTTN has been identified as an interactor of GSN, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human GSN and recombinant human CTTN. Briefly, biotin-linked GSN were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100µl were then transferred to CTTN-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST 3 times and incubation with Streptavidin-HRP for 30min, then wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50µl stop solution to the wells and read at 450nm immediately. The binding activity of GSN and CTTN was shown in Figure 1, the EC50 for this effect is 0.30181µg/mL.