Controlling cytoskeleton structure by phosphoinositide-protein interactions: phosphoinositide binding protein domains and effects of lipid packing

Cell movement and resistance to mechanical forces are largely governed by t he cytoskeleton, a three-dimensional network of protein filaments that form viscoelastic networks within the cytoplasm. The cytoskeleton underlying th e plasma membrane of most cells is rich in actin filaments whose assembly a nd disassembly are regulated by actin binding proteins that are stimulated or inhibited by signals received and transmitted at the membrane/cytoplasm interface. Inositol phospholipids, or phosphoinositides, are potent regulat ors of many actin binding proteins, and changes in the phosphorylation of s pecific phosphoinositide species or in their spatial localization are assoc iated with cytoskeletal remodeling in vitro. This review will focus on rece nt studies directed at defining the structural features of phosphoinositide binding sites in actin binding proteins and on the influence of the physic al state of phosphoinositides on their ability to interact with their targe t proteins. (C) 1999 Published by Elsevier Science Ireland Ltd. All rights reserved.