- calponin-homology (CH) domain
- formin-homology-2 (FH2) domain
- WASp-homology-2 (WH2) domain
- actin-depolymerizing factor/cofilin (ADF/cofilin) domain
- gelsolin-homology domain
- myosin motor domain
Although functionally similar, other cross-linking proteins may promote the formation of larger networks, or filamentous structures, in different regions of the cell. Generally, proteins with similar functions (e.g. fascin, α-actinin) act cooperatively to enhance the mechanical integrity and responsiveness of the network  (reviewed in ).
Phalloidins bind to actin filaments at a ratio of one molecule for either one or two actin protomers and essentially lock adjacent actin subunits together. This shifts the equilibrium to favour filament formation over filament disassembly. As filament formation is normally a balance between monomer association and filament dissociation, blocking the latter step reduces the critical concentration of free monomers required to maintain filament elongation. (reviewed in ).
Unlike Latrunculin A, the cytochalasins bind actin filaments rather than G-actin monomers. Binding occurs at a ratio of one molecule per filament, and binding occurs selectively at the barbed end of the filaments. This effectively blocks association (and dissociation) of actin monomers at the barbed end, halting further elongation of filaments .
12, 13]. These include inducing spontaneous nucleation of G-actin monomers and actin polymerization. Disorganized F-actin aggregates have been observed in vivo as a result of spontaneous nucleation as has an increase in the density of actin filaments adjacent to the plasma membrane. Like phalloidin, jasplakinolide stabilizes F-actin filaments by inihibiting filament disassembly. Whilst the two drugs have substantially different structures, jasplakinolide has been shown to bind competitively with phalloidin to F-actin , suggesting a similar binding mechanism, and possibly a similar mode of action. As G-actin levels are depleted following jasplakinolide treatment a reduction in stress fibers are also known to be reduced by the drug.