F-actin cross-linking protein which is thought to anchor actin to a variety of intracellular structures. This is a bundling protein. Probably involved in vesicular trafficking via its association with the CART complex. Involved in tight junction assembly in epithelial cells. May also function as a transcriptional coactivator, stimulating transcription mediated by nuclear hormone receptors. Homodimer; antiparallel. Component of the CART complex. May interact with nuclear receptors. Contains one Leu-Xaa-Xaa-Leu-Leu (LXXLL) motif that may mediate interaction with nuclear receptors. Belongs to the alpha-actinin family.