Cortactin is a cytoplasmic protein that is involved in the regulation of actin dynamics and cell motility. It is expressed in a wide range of tissues and plays a key role in processes such as cell adhesion, migration, and invasion.

Cortactin is a multi-domain protein that contains several functional domains, including an N-terminal acidic region, a central proline-rich region, and a C-terminal Src homology 3 (SH3) domain. The N-terminal acidic region is involved in the binding of cortactin to the plasma membrane, while the proline-rich region mediates interactions with other proteins, such as the actin-binding protein N-WASP. The SH3 domain is responsible for binding to other proteins, such as the tyrosine kinase Src.

Cortactin is regulated by a variety of signaling pathways, including those involving tyrosine kinases, small GTPases, and phosphatidylinositol 3-kinase (PI3K). Dysregulation of cortactin has been implicated in several diseases, including cancer and neurological disorders.