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Title: Stress fiber strain recognition by the LIM protein testin is cryptic and mediated by RhoA
The actin cytoskeleton is a key regulator of mechanical processes in cells. The family of LIM domain proteins have recently emerged as important mechanoresponsive cytoskeletal elements capable of sensing strain in the actin cytoskeleton. The mechanisms regulating this mechanosensitive behavior, however, remain poorly understood. Here we show that the LIM domain protein testin is peculiar in that despite the full-length protein primarily appearing diffuse in the cytoplasm, the C-terminal LIM domains alone recognize focal adhesions and strained actin, while the N-terminal domains alone recognize stress fibers. Phosphorylation mutations in the dimerization regions of testin, however, reveal its mechanosensitivity and cause it to relocate to focal adhesions and sites of strain in the actin cytoskeleton. Finally, we demonstrate that activated RhoA causes testin to adorn stress fibers and become mechanosensitive. Together, our data show that testin’s mechanoresponse is regulated in cells and provide new insights into LIM domain protein recognition of the actin cytoskeleton’s mechanical state.  more » « less
Award ID(s):
2000554
PAR ID:
10316486
Author(s) / Creator(s):
;
Editor(s):
Dunn, Alex
Date Published:
Journal Name:
Molecular Biology of the Cell
Volume:
32
Issue:
18
ISSN:
1059-1524
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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