Adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions and may be involved in various processes including cellular proliferation, migration, adhesion and attachment. May play a role in ER stress response (By similarity). May participate in the genesis and function of cardiac and skeletal muscle. Homotrimer; disulfide-linked. Initial expression during neurulation. Increase during tailbud stages but decrease by the feeding tadpole stage. Belongs to the thrombospondin family.