生体膜と細胞骨格系の機能的相互作用 イノシトールリン脂質（ホスホイノシチド）によるアクチン細胞骨格系の制御

Abstract

The cytoskeleton and the plasma membrane are two major components that define cellular shape, and control cell movement. The actin cytoskeleton lies just beneath the plasma membrane suggesting regulatory mechanisms based upon direct interactions between them. In fact, almost all of actin regulating proteins are known to bind phospholipids, especially phosphoinositides, to enhance or to suppress their activity. Such examples include the “classical” actin regulating proteins (profilin, gelsolin etc.) as well as recently unveiled ERM proteins and WASP families. In addition, interference of interaction between phosphoinositide and those proteins by a specific antibody or a phosphoinositide-binding peptide results in an inhibition of actin polymerization in response to extracellular stimuli. Furthermore, disturbance of intracellular phosphoinositide content by overexpression of phosphoinositide kinases or phosphatases affects the structure of actin cytoskeleton. These data clearly indicate the close relationship between phosphoinositide and actin cytoskeleton, and suggest the existence of the regulatory mechanism of cytoskeleton by phosphoinositide metabolizing enzymes. This review will focus on actin regulating proteins controlled by phosphoinositides and discuss their roles for cytoskeletal rearrangements upon extracellular signals.