Amelogenin, the major component of a commercial enamel matrix derivative (Straumann® Emdogain), is commonly employed in periodontology. It is mainly used in periodontal surgery to stimulate the regeneration of periodontal tissues, including the cementum, periodontal ligament, and alveolar bone. However, the precise molecular mechanisms underlying amelogenin-induced regeneration have not yet been elucidated. Thus, to gain further insight into how amelogenin induces periodontal tissue regeneration, we performed a protein interaction screen using recombinant full-length amelogenin (rM180) as bait. Coupling affinity chromatography with proteomic analysis identified glucose-regulated protein 78 (Grp78) as a new amelogenin-binding protein. We further demonstrated that the interaction between amelogenin and Grp78 not only contributes to cell proliferation in osteoblastic cells but also enhances cell migration in periodontal ligament stem/progenitor cells. Although the potentiation effects of Grp78 should be further examined in vivo, our findings indicate the significant therapeutic potential for amelogenin-induced periodontal tissue regeneration.