Dynamic organization of the actin system in the motile cells of Dictyostelium

摘要: The actin system forms a supramolecular, membrane-associated network that serves multiple functions in Dictyostelium cells, including cell motility controlled by chemoattractant, phagocytosis, macropinocytosis, and cytokinesis. In executing these the monomeric G-actin polymerizes reversibly, filaments are assembled into membrane-anchored networks together with other proteins involved shaping controlling their dynamics. Most impressive is speed at which actin-based structures built, reorganized, or disassembled. We used GFP-tagged coronin Arp3, an intrinsic constituent of Arp2/3 complex, as examples recruited to highly dynamic actin-filament networks. By fluorescence recovery after photobleaching (FRAP), average exchange rates cell-cortex bound were estimated. A nominal value 5 s for half-maximal incorporation cortex, 7 dissociation from cortical binding sites has been obtained. Actin dynamics implies also flow F-actin polymerization depolymerization, i.e. tail migrating cell, base phagocytic cup, cleavage furrow mitotic cell. To monitor this flow, we expressed cells actin-binding fragment talin. This (GFP-TalC63) translocates front during migration polar regions division. can be manipulated vivo drugs probes act either inhibitors stabilizers filamentous actin. order investigate structure–function relationships system, technique reliably arresting transient demand. discuss potential electron tomography vitrified visualize native association membranes.