Tetraspanins: integrating cell surface receptors to functional microdomains in homeostasis and disease.

Tetraspanins comprise a family of proteins embedded in the membrane through four transmembrane domains. One of the most distinctive features of tetraspanins is their ability to interact with other proteins in the membrane using their extracellular, transmembrane and cytoplasmic domains, allowing them to incorporate several proteins into clusters called tetraspanin-enriched microdomains. The spatial proximity of signaling proteins and their regulators enables a rapid functional cross-talk between these proteins, which is required for a rapid translation of extracellular signals into intracellular signaling cascades. In this article, we highlight a few examples that illustrate how tetraspanin-mediated interactions between cell surface proteins allow their functional cross-talk to regulate intracellular signaling.