Thrombospondin 1 (THBS1) is a matricellular glycoprotein that critically mediates cell–matrix interactions. It promotes cell adhesion by binding to cell surface receptors, including integrins such as αvβ3 and α4β1, and non-integrin receptors like CD36 and CD47. Through its multiple domains, THBS1 forms a molecular bridge between the extracellular matrix and the cell membrane, facilitating focal adhesion assembly and cytoskeletal organization. This adhesive function is essential for modulating cellular processes such as migration, proliferation, and survival, positioning THBS1 as a key regulator in tissue remodeling, wound healing, and angiogenesis. As THBS1 has the function of cell adhesion, we measure the activity of recombinant mouse THBS1 by the ability of the immobilized protein to support the adhesion of AGS cell. When cells are added to different concentrations of recombinant mouse THBS1 coated plates, cells will adhere after 2 hour incubation at 37 ℃. The adhesion of AGS after 2 hour incubation at 37 ℃ observed by inverted microscope was shown in Figure 1. Cell adherent was in a dose dependent manner, the result was shown in Figure 2, the EC50 was 0.6 μg/ml.