Alfa-actinin4 is a cytoskeletal protein and actin cross-linker encoded by the ACTN4 gene, and is a member of the spectrin superfamily of cytoskeletal proteins. Together with isoform 1, actinin-4 is found in nearly every nonmuscle cell but also in cancer cells. The N-terminal pair of Calponin-homology domains constitute an actin binding site whereas the spectrin repeats likely form a rod-like domain. It forms homodimers and has been observed to shuttle between nucleus and cytoplasm under certain conditions. Alfa-actinin function is not restricted to cell motility and cytoskeletal organization, but extends to modulation of gene expression, apoptosis and endocytosis. Actinin-4 deficient mice develop proteinurea and glomerular disease