In situ observation on hierarchical actin bundle networks; Salt concentration effects

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

Actin is one of the cytoskeleton proteins and it is most abundant proteins in eucaryotic cell. They play a crucial role in cell motility by polymerization of monomeric globular G-actin into polymeric filamentous actin (F-actin). With actin binding proteins, they form various structures such as linear bundles, two-dimensional networks, and three-dimensional gels. It has been considered that these structures are controlled by the specific interaction between actin and binding protein. However from the physicochemical point of view, actin has negative charge and actin-binding protein has positive charge. Thus, the electrostatic interaction might play important role to determinein the structure. Based on this idea, we have investigated the effects of salt concentration on the stability and structure of actin-polymer complexes by using small angle neutron scattering (SANS) technique.