Evolutionary tuning of barbed end competition allows simultaneous construction of architecturally distinct actin structures

J Cell Biol. 2023 Apr 3;222(4):e202209105. doi: 10.1083/jcb.202209105. Epub 2023 Feb 2.


How cells simultaneously assemble actin structures of distinct sizes, shapes, and filamentous architectures is still not well understood. Here, we used budding yeast as a model to investigate how competition for the barbed ends of actin filaments might influence this process. We found that while vertebrate capping protein (CapZ) and formins can simultaneously associate with barbed ends and catalyze each other's displacement, yeast capping protein (Cap1/2) poorly displaces both yeast and vertebrate formins. Consistent with these biochemical differences, in vivo formin-mediated actin cable assembly was strongly attenuated by the overexpression of CapZ but not Cap1/2. Multiwavelength live cell imaging further revealed that actin patches in cap2∆ cells acquire cable-like features over time, including recruitment of formins and tropomyosin. Together, our results suggest that the activities of S. cerevisiae Cap1/2 have been tuned across evolution to allow robust cable assembly by formins in the presence of high cytosolic levels of Cap1/2, which conversely limit patch growth and shield patches from formins.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actin Capping Proteins* / metabolism
  • Actin Cytoskeleton / metabolism
  • Actins* / metabolism
  • CapZ Actin Capping Protein / metabolism
  • Cytosol / metabolism
  • Formins / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins* / metabolism


  • Actin Capping Proteins
  • Actins
  • CAP1 protein, S cerevisiae
  • Formins
  • Saccharomyces cerevisiae Proteins
  • Cap2 protein, S cerevisiae
  • CapZ Actin Capping Protein