The 2.0Å Structure of the Second Calponin Homology Domain from the Actin-binding Region of the Dystrophin Homologue Utrophin

1999 ◽  
Vol 285 (3) ◽  
pp. 1257-1264 ◽  
Author(s):  
Nicholas H. Keep ◽  
Fiona L.M. Norwood ◽  
Carolyn A. Moores ◽  
Steven J. Winder ◽  
John Kendrick-Jones

Biochemistry ◽  
2017 ◽  
Vol 56 (20) ◽  
pp. 2627-2636 ◽  
Author(s):  
Surinder M. Singh ◽  
Swati Bandi ◽  
Krishna M. G. Mallela


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Saravanan Palani ◽  
Sayantika Ghosh ◽  
Esther Ivorra-Molla ◽  
Scott Clarke ◽  
Andrejus Suchenko ◽  
...  

Actin filaments are central to numerous biological processes in all domains of life. Driven by the interplay with molecular motors, actin binding and actin modulating proteins, the actin cytoskeleton exhibits a variety of geometries. This includes structures with a curved geometry such as axon-stabilizing actin rings, actin cages around mitochondria and the cytokinetic actomyosin ring, which are generally assumed to be formed by short linear filaments held together by actin cross-linkers. However, whether individual actin filaments in these structures could be curved and how they may assume a curved geometry remains unknown. Here, we show that 'curly', a region from the IQGAP family of proteins from three different organisms, comprising the actin-binding calponin-homology domain and a C-terminal unstructured domain, stabilizes individual actin filaments in a curved geometry when anchored to lipid membranes. Whereas F-actin is semi-flexible with a persistence length of ~10 mm, binding of mobile curly within lipid membranes generates actin filament arcs and full rings of high curvature with radii below 1 mm. Higher rates of fully formed actin rings are observed in the presence of the actin-binding coiled-coil protein tropomyosin and when actin is directly polymerized on lipid membranes decorated with curly. Strikingly, curly induced actin filament rings contract upon the addition of muscle myosin II filaments and expression of curly in mammalian cells leads to highly curved actin structures in the cytoskeleton. Taken together, our work identifies a new mechanism to generate highly curved actin filaments, which opens a range of possibilities to control actin filament geometries, that can be used, for example, in designing synthetic cytoskeletal structures.



Biochemistry ◽  
2014 ◽  
Vol 53 (11) ◽  
pp. 1801-1809 ◽  
Author(s):  
Surinder M. Singh ◽  
Swati Bandi ◽  
Steve J. Winder ◽  
Krishna M. G. Mallela


2016 ◽  
Vol 473 (16) ◽  
pp. 2485-2493 ◽  
Author(s):  
Natalie J. Haywood ◽  
Marcin Wolny ◽  
Brendan Rogers ◽  
Chi H. Trinh ◽  
Yu Shuping ◽  
...  

We have discovered that two mutations at the actin binding domain (ABD) of α-actinin-2 (ACTN2), which cause hypertrophic cardiomyopathy (HCM), have minor effects on its structure and ability to bind actin and integrate into Z-discs, providing a potential disease mechanism.



2019 ◽  
Vol 30 (26) ◽  
pp. 3112-3122 ◽  
Author(s):  
Andrew R. Harris ◽  
Brian Belardi ◽  
Pamela Jreij ◽  
Kathy Wei ◽  
Hengameh Shams ◽  
...  

We show that the affinity of CH1–CH2 domains for F-actin can be both increased and decreased by diverse modifications that change the effective “openness” of CH1 and CH2, which sterically regulates binding to F-actin. We also show that subcellular localization depends on the N-terminal flanking region of CH1 but not on the overall affinity for F-actin.



2020 ◽  
Author(s):  
Saravanan Palani ◽  
Mohan K. Balasubramanian ◽  
Darius V. Köster

Actin filaments are central to numerous biological processes in all domains of life. Driven by the interplay with molecular motors, actin binding and actin modulating proteins, the actin cytoskeleton exhibits a variety of geometries. This includes structures with a curved geometry such as axon-stabilizing actin rings, actin cages around mitochondria and the cytokinetic actomyosin ring, which are generally assumed to be formed by short linear filaments held together by actin cross-linkers. However, whether individual actin filaments in these structures could be curved and how they may assume a curved geometry remains unknown. Here, we show that “curly”, a region from the IQGAP family of proteins from three different organisms, comprising the actin-binding calponin-homology domain and a C-terminal unstructured domain, stabilizes individual actin filaments in a curved geometry when anchored to lipid membranes. Whereas F-actin is semi-flexible with a persistence length of ∼10 μm, binding of mobile curly within lipid membranes generates actin filament arcs and full rings of high curvature with radii below 1 μm. Higher rates of fully formed actin rings are observed in the presence of the actin-binding coiled-coil protein tropomyosin, and also when actin is directly polymerized on lipid membranes decorated with curly. Strikingly, curly induced actin filament rings contract upon the addition of muscle myosin II filaments and expression of curly in mammalian cells leads to highly curved actin structures in the cytoskeleton. Taken together, our work identifies a new mechanism to generate highly curved actin filaments, which opens a new range of possibilities to control actin filament geometries, that can be used, for example, in designing synthetic cytoskeletal structures.



1997 ◽  
Vol 4 (3) ◽  
pp. 175-179 ◽  
Author(s):  
Kristina Djinovic Carugo ◽  
Sonia Bañuelos ◽  
Matti Saraste


2011 ◽  
Vol 108 (31) ◽  
pp. 12729-12733 ◽  
Author(s):  
A. Y. Lin ◽  
E. Prochniewicz ◽  
Z. M. James ◽  
B. Svensson ◽  
D. D. Thomas


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