Functional ligand of integrin alpha-8/beta-1 in kidney development. Regulates the expression of GDNF with integrin alpha-8/beta-1 which is essential for kidney development. May also play a role in the development and function of various tissues, regulating cell adhesion, spreading and survival through the binding of several integrins. Homodimer and homotrimer. Trapped on the cell surface or in the extracellular matrix. Expressed in kidney (at protein level). Expressed from 10.5 dpc onward mainly at epithelial-mesenchymal interfaces in kidney and other tissues undergoing morphogenesis (at protein level). The MAM domain is required for localization at the cell surface. Mice display renal agenesis at birth due to a developmental delay. This delay is associated with a reduced expression of Gdnf and is similar to the one found in mice lacking Itga8. Was named nephronectin based on its potential role in kidney development. Belongs to the nephronectin family.