Hyaluronan in the pericellular coat: an additional layer of complexity in early cell adhesion events

Cell adhesion is a multistage process whereby specific surface receptors interact with the corresponding ligands on the extracellular matrix or on neighboring cells. These complex interactions involve a wide variety of cellular molecules including transmembrane and cytoskeletal components, scaffolding proteins, and a wide variety of signaling enzymes. In this article we discuss recent data characterizing the involvement of the pericellular hyaluronan coat in early stages of cell-matrix adhesion. In particular, we address the mechanisms underlying the transition from hyaluronan- to integrin-mediated adhesion, and the role of the actin cytoskeleton in the "inside-out" regulation and maintenance of the pericellular hyaluronan coat.