Grancalcin (GCA) is a cytoplasmic granule membrane protein that contains 4 EF-hand domains. GCA is calcium-binding protein and particularly abundant in human neutrophils. GCA is highly expressed in bone marrow, and it can be detected in neutrophils and macrophages. Calcium-binding protein GCA cooperates with SRI and LCP1, so it may play a role in the adhesion of neutrophils to fibronectin. GCA also may play a role in the formation of focal adhesions.