Predicted to enable calcium ion binding activity and growth factor activity. Acts upstream of or within tendon development. Predicted to be located in extracellular space and sarcoplasmic reticulum. Predicted to be active in collagen-containing extracellular matrix. Is expressed in cranial cartilage; musculature system; notochord; pectoral fin; and trunk. Orthologous to human THBS4 (thrombospondin 4).