AI Article Synopsis
- Formins are proteins that help build actin networks in cells, but how their activity is regulated is not fully understood.
- In yeast, formins create actin cables used for transporting materials, and a protein called Smy1 interacts with a specific part of the formin Bnr1 to slow down the growth of these actin filaments.
- This slowing mechanism is crucial for maintaining the structure and function of actin cables, as shown by experiments with mutants lacking Smy1, indicating that Smy1 helps prevent excessive growth of the cables.
Article Abstract
Formins are a conserved family of proteins with robust effects in promoting actin nucleation and elongation. However, the mechanisms restraining formin activities in cells to generate actin networks with particular dynamics and architectures are not well understood. In S. cerevisiae, formins assemble actin cables, which serve as tracks for myosin-dependent intracellular transport. Here, we show that the kinesin-like myosin passenger-protein Smy1 interacts with the FH2 domain of the formin Bnr1 to decrease rates of actin filament elongation, which is distinct from the formin displacement activity of Bud14. In vivo analysis of smy1Δ mutants demonstrates that this "damper" mechanism is critical for maintaining proper actin cable architecture, dynamics, and function. We directly observe Smy1-3GFP being transported by myosin V and transiently pausing at the neck in a manner dependent on Bnr1. These observations suggest that Smy1 is part of a negative feedback mechanism that detects cable length and prevents overgrowth.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157649 | PMC |
| http://dx.doi.org/10.1016/j.devcel.2011.07.004 | DOI Listing |
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