Cytonectin expression in Alzheimer disease.

Cytonectin is a novel 35,000 molecular weight protein that displays remarkable ion-independent adherence properties. This consigns it to a family of well-known adherence molecules essential for cell communication and the development of 3-dimensional tissue structures. Cytonectin is expressed in a variety of organs and tissues, being evolutionarily conserved from human to avian species. It is hypothesized to serve as a key structural component of the body, and as a "do not attack" signal molecule that prevents tissue destruction by cells of monocyte lineage. This paper describes the properties of cytonectin and its proposed role in normal and disease states. The protein is overexpressed in Alzheimer disease entorhinal cortex as compared to normal age-matched controls. It is also detected in tissues from patients with Down syndrome and leukemia. Its presence in all 3 of these related conditions may prove important to their etiopathogenesis.