POSTN contains an N-terminal secretory signal peptide followed by an EMI domain, the four-repeat FAS1 domain, and a CTD. Collagen I and fibronectin can bind to the EMI domain; the four-repeat FAS1 domain can interact with tenascin C, BMP-1, CCN3, and integrins; CTD contains an arginine-rich heparin binding site, which can bind to proteoglycans. POSTN can play an important role between the cell and the surrounding microenvironment due to its fine composition structure. The image is adapted from Zhu et al. (2021)