Role of Actin Filament Organization in Ion Channel Activity and Cell Volume Regulation

CANTIELLO HF; PRAT AG

Membrane Protein-Cytoskeleton Interactions

Academic Press

Año: 1996; p. 373 - 396

This chapter describes the role of actin-filament organization on ion-channel activity and cell-volume regulation. Actin can be found in several different states within the intracellular compartment. Dynamic transitions entailing changes from one conformation to another may be central to such mechanically related events as cell locomotion and rounding, cytokinesis and spreading, and intracellular transport to the cell surface. Actin filaments may be also linked to osmotically induced phase transitions, which in turn may represent novel electroosmotic signaling events. These proteins therefore help maintain a balance between G- and F-actin concentrations. Another important family of ABPs, however, actually binds already formed actin filaments (F-actin). Most F-actin-binding proteins are known to have at least two actin-binding domains, thus allowing coupling to more than one actin filament. Depending on the distance between the actin-binding domains, these proteins may enable either the bundling of actin (tightly packed arrays of filaments), as observed in the complexes of F-actin found in microvilli, or the crosslinking of actin into 3-dimensional actin filament networks with gel behavior.