Mechanisms of integrin-mediated virus attachment and internalization process.

Viruses that propagate within vertebrate hosts have adapted many strategies to infect host cells. One of the first steps in a viral infection is the binding of the virus to cell surface molecules. This interaction between a virus and its receptors plays a key role in the multiplication cycle. Entry of viruses into cells is a complex, multistep process, and for several viruses, cell attachment and internalization are distinct steps. A number of virus receptors have been identified; a common family of viral receptors is the integrin family. Integrins are a widely expressed family of cell adhesion receptors, by which cells attach to extracellular matrices; they also mediate important cell-cell adhesion events. Integrins are involved in a number of tissue remodeling events, including embryogenesis, angiogenesis, wound repair, and bone resorption. In addition, several integrins are used by manyviruses in theirinfectious cycle. Virus-integrin interactions maybe more complex than previously thought because several viruses can interact with unique integrin regions or can activate distinct signaling pathways. This article will discuss the strategies devised by many viruses in their integrin-mediated attachment or cell entry.