Gelsolin (GSN) is a ubiquitous, multifunctional actin-binding protein that plays a pivotal role in remodeling the cytoskeleton by severing, capping, and nucleating actin filaments. This calcium-dependent regulation is essential for critical cellular processes including cell motility, shape changes, and the clearance of cellular debris post-injury. By controlling the dynamics of actin assembly and disassembly, GSN influences a wide range of physiological functions from wound healing to platelet activation. Importantly, GSN directly binds to ACTC1, the primary actin isoform in cardiac muscle, to regulate the contractile apparatus and maintain heart function.To detect the activity of recombinant GSN , a functional ELISA assay was performed to evaluate the interaction between recombinant mouse GSN and recombinant human ACTC1.Briefly, GSN was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to ACTC1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-GSN pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μL stop solution to the wells and read at 450/630nm immediately. The binding activity of recombinant mouse GSN and recombinant human ACTC1 was shown in Figure 1, the EC50?for this effect is 0.38μg/mL.