Focal adhesions contain three specialized actin nanoscale layers




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

PublisherNature Research

2024

Nature Communications

NATURE COMMUNICATIONS

ARTN 2547

15

1

2041-1723

DOIhttps://doi.org/10.1038/s41467-024-46868-7(external)

https://doi.org/10.1038/s41467-024-46868-7(external)

https://research.utu.fi/converis/portal/detail/Publication/387698907(external)



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.


Last updated on 2024-26-11 at 16:06