Vinexin is a 671 amino acid protein that is expressed as two isoforms, designated Vinexin alpha and Vinexin beta. Localized to cell junctions in both the cytoplasm and the cytoskeleton, Vinexin alpha functions to promote Actin stress fiber formation, playing an important role in modification of the Actin cytoskeleton. Like Vinexin alpha, Vinexin beta is localized to cell junctions in the cytoplasm, but is also found in the nucleus where it plays an important role in cell spreading and in activation of the JNK pathway in response to EGF stimulation. Although Vinexin alpha and Vinexin beta have different roles within the cell, both proteins contain three SH3 domains in their carboxy terminus and are expressed in a variety of tissues, including placenta, heart, liver, brain, pancreas and skeletal muscle. Together, Vinexin alpha and Vinexin beta are involved in cell-cell adhesion, signal transduction and cytoskeletal organization throughout the cell.