Transduction of extracellular matrix signals through integrins influences intracellular and extracellular functions, and appears to require interaction of integrin cytoplasmic domains with cellular proteins. Integrin linked kinase (ILK), interacts with the cytoplasmic domain of beta 1 Integrin. ILK encodes a predicted 451 amino acid protein, with an apparent molecular weight of 59 kDa. The ILK protein is a serine/threonine protein kinase with 4 ankyrin like repeats. ILK regulates integrin mediated signal transduction.
The ILK protein is important in different biological pathways such as cell adhesion, anchorage-dependent cell cycle progression, oncogenic transformation, and growth factor signaling. The kinase activity of ILK is low in non-activated cells; its activity is stimulated by cell-ECM interactions and by certain growth factors. 3 Negative regulation of ILK is mediated by two phosphatases: PTEN, a tumor suppressor lipid sphatase, and ILKAP, a PP2C protein phosphatase. In tumor cells that do not express PTEN protein, ILK is constitutively active.