The Cytokinesis Formins from the Nematode Worm and Fission Yeast Differentially Mediate Actin Filament Assembly

摘要: Formins drive actin filament assembly for diverse cellular processes including motility, establishing polarity, and cell division. To investigate the mechanism of contractile ring in animal cells, we directly compared properties formins required cytokinesis nematode worm early embryo (CYK-1) fission yeast (Cdc12p). Like Cdc12p most other formins, CYK-1 nucleates remains processively associated with elongating barbed end while facilitating addition profilin-actin above theoretical diffusion-limited rate. However, specific differ significantly between CYK-1. efficiently filaments that presence profilin elongate at approximately same rate as control without formin (∼10.0 subunits/s). is an inefficient nucleator but allows to 6-fold faster than (∼60 Both bind pre-assembled low nanomolar affinity, dissociates 2 orders magnitude more quickly. rapidly re-associates free ends. ends excess capping protein, whereas protein inhibits CYK-1-mediated assembly. Therefore, these evolutionarily can by a generally similar mechanism, cells unique dimensions physical parameters might require proteins carefully tuned properties.