DAAM1 formin and Ena/VASP proteins assemble functionally distinct actin filaments for focal adhesions

Authors

Chua, X. L., Biswas, P., Wioland, H., Lappalainen, P.

Abstract

Eukaryotic cells contain multiple biochemically distinct actin filament networks, which enable versatile functions of actin in a range of cellular processes. Yet, the mechanisms by which specific actin filament networks are assembled in a common cytoplasm remain elusive. Here, we investigated how functionally distinct actin nanoscale layers, specified by -actininand tropomyosin isoforms, Tpm1.6 and Tpm3.2, are assembled at focal adhesions. By combining genetic perturbations with mitochondrial-targeting of actin polymerases, we discovered that DAAM1 formin assembles Tpm3.2-actin filaments, whereas Ena/VASP family proteins polymerize -actinin cross-linked actin filament bundles at focal adhesions. Consequently, loss of DAAM1 dampened Tpm3.2 protein levels and impaired focal adhesion disassembly, thus phenocopying Tpm3.2-deficient cells. In contrast, Ena/VASP depletion led to defective focal adhesion maturation and loss of -actinin from focal adhesions. More broadly, our study highlights specific roles for formin and Ena/VASP family proteins in assembling biochemically and functionally distinct linear actin filament arrays in cells.

Preprint server: bioRxiv
The authors list and abstract were imported from bioRxiv on 21 Aug 2026.

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