A1 Refereed original research article in a scientific journal
Focal adhesions contain three specialized actin nanoscale layers
Authors: Kumari Reena, Ven Katharina, Chastney Megan, Kokate Shrikant B., Peränen Johan, Aaron Jesse, Kogan Konstantin, Almeida-Souza Leonardo, Kremneva Elena, Poincloux Renaud, Chew Teng-Leong, Gunning Peter W., Ivaska Johanna, Lappalainen Pekka
Publisher: Nature Research
Publication year: 2024
Journal: Nature Communications
Journal name in source: NATURE COMMUNICATIONS
Article number: ARTN 2547
Volume: 15
Issue: 1
eISSN: 2041-1723
DOI: https://doi.org/10.1038/s41467-024-46868-7
Web address : https://doi.org/10.1038/s41467-024-46868-7
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/387698907
Focal adhesions (FAs) connect inner workings of cell to the extracellular matrix to control cell adhesion, migration and mechanosensing. Previous studies demonstrated that FAs contain three vertical layers, which connect extracellular matrix to the cytoskeleton. By using super-resolution iPALM microscopy, we identify two additional nanoscale layers within FAs, specified by actin filaments bound to tropomyosin isoforms Tpm1.6 and Tpm3.2. The Tpm1.6-actin filaments, beneath the previously identified α-actinin cross-linked actin filaments, appear critical for adhesion maturation and controlled cell motility, whereas the adjacent Tpm3.2-actin filament layer beneath seems to facilitate adhesion disassembly. Mechanistically, Tpm3.2 stabilizes ACF-7/MACF1 and KANK-family proteins at adhesions, and hence targets microtubule plus-ends to FAs to catalyse their disassembly. Tpm3.2 depletion leads to disorganized microtubule network, abnormally stable FAs, and defects in tail retraction during migration. Thus, FAs are composed of distinct actin filament layers, and each may have specific roles in coupling adhesions to the cytoskeleton, or in controlling adhesion dynamics.
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