The Actin Binding Affinity of the Utrophin Tandem Calponin-Homology Domain Is Primarily Determined by Its N-Terminal Domain

Biochemistry ◽  
2014 ◽  
Vol 53 (11) ◽  
pp. 1801-1809 ◽  
Author(s):  
Surinder M. Singh ◽  
Swati Bandi ◽  
Steve J. Winder ◽  
Krishna M. G. Mallela
Keyword(s):  
Binding Affinity ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Terminal Domain

The N-Terminal Flanking Region Modulates the Actin Binding Affinity of the Utrophin Tandem Calponin-Homology Domain

Biochemistry ◽  
2017 ◽  
Vol 56 (20) ◽  
pp. 2627-2636 ◽  
Author(s):  
Surinder M. Singh ◽  
Swati Bandi ◽  
Krishna M. G. Mallela
Keyword(s):  
Binding Affinity ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Flanking Region

scholarly journals Steric regulation of tandem calponin homology domain actin-binding affinity

2019 ◽  
Vol 30 (26) ◽  
pp. 3112-3122 ◽  
Author(s):  
Andrew R. Harris ◽  
Brian Belardi ◽  
Pamela Jreij ◽  
Kathy Wei ◽  
Hengameh Shams ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Binding Affinity ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Flanking Region

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.

Abstract 42: Differential Contribution Of The N- And C-terminal Domains To The Folding And Function Of Tandem Calponin-homology Domains

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Krishna Mallela ◽  
Swati Bandi ◽  
Surinder Singh ◽  
Geoffrey Armstrong
Keyword(s):  
Full Length ◽  
Actin Binding ◽  
Main Function ◽  
Calponin Homology ◽  
Terminal Domain ◽  
Binding Domains ◽  
Binding Function ◽  
Ch2 Domain ◽  
The Stability ◽  
And Function

Tandem calponin-homology (CH) domains constitute a major class of actin-binding domains that include dystrophin and utrophin, the two key proteins involved in muscular dystrophy. Despite their importance, how their structure controls their function is not understood. Here, we study the contribution of individual CH domains to the actin-binding function and thermodynamic stability of utrophin’s tandem CH domain. Traditional actin co-sedimentation assays indicate that the isolated C-terminal CH2 domain binds weakly to F-actin when compared with the full-length tandem CH domain. In contrast, isolated CH1 binds to F-actin with a similar efficiency as that of the full-length tandem CH domain. Thus, the obvious question that arises is why tandem CH domains require CH2, when their actin-binding efficiency is originating primarily from CH1. To answer, we probed the thermodynamic stabilities of individual CH domains. Isolated CH1 domain is unstable and is prone to serious aggregation. Isolated CH2 is very stable, even appears to be more stable than the full-length tandem CH domain. In addition, the CH2 domain, which is more stable, is less functional. These results indicate that the main function of CH2 is to stabilize CH1. Consistently, the proposed structure of utrophin’s tandem CH domain based on earlier X-ray studies indicates a close proximity between the C-terminal helix of CH2 and the N-terminal helix of CH1, and this helix in CH2 is more dynamic in the full-length protein when compared with that in the absence of CH1, suggesting the mechanism by which CH2 stabilizes CH1. These observations indicate that the two CH domains contribute differentially to the folding and function of tandem CH domains, although both domains essentially have the same native structure in the tandem CH domain. The N-terminal domain determines the function, whereas the C-terminal domain determines the stability. This work was funded by the AHA Grant 11SDG4880046.

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
Keyword(s):  
Actin Binding ◽  
Calponin Homology Domain ◽  
Binding Region ◽  
Calponin Homology

scholarly journals Calponin-homology domain mediated bending of membrane associated actin filaments

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Saravanan Palani ◽  
Sayantika Ghosh ◽  
Esther Ivorra-Molla ◽  
Scott Clarke ◽  
Andrejus Suchenko ◽  
...  
Keyword(s):  
Actin Filament ◽  
Molecular Motors ◽  
Lipid Membranes ◽  
Actin Filaments ◽  
Mammalian Cells ◽  
Persistence Length ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Actin Rings

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.

scholarly journals Hypertrophic cardiomyopathy mutations in the calponin-homology domain of ACTN2 affect actin binding and cardiomyocyte Z-disc incorporation

2016 ◽  
Vol 473 (16) ◽  
pp. 2485-2493 ◽  
Author(s):  
Natalie J. Haywood ◽  
Marcin Wolny ◽  
Brendan Rogers ◽  
Chi H. Trinh ◽  
Yu Shuping ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Binding Domain ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Disease Mechanism ◽  
Calponin Homology ◽  
Actin Binding Domain ◽  
Cardiomyopathy Mutations

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.

The C-Terminal Domain of the Utrophin Tandem Calponin-Homology Domain Appears To Be Thermodynamically and Kinetically More Stable Than the Full-Length Protein

Biochemistry ◽  
2014 ◽  
Vol 53 (14) ◽  
pp. 2209-2211 ◽  
Author(s):  
Swati Bandi ◽  
Surinder M. Singh ◽  
Krishna M. G. Mallela
Keyword(s):  
Full Length ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Terminal Domain

scholarly journals Calponin-Homology Domain mediated bending of membrane associated actin filaments

2020 ◽  
Author(s):  
Saravanan Palani ◽  
Mohan K. Balasubramanian ◽  
Darius V. Köster
Keyword(s):  
Actin Filament ◽  
Molecular Motors ◽  
Lipid Membranes ◽  
Actin Filaments ◽  
Mammalian Cells ◽  
Persistence Length ◽  
Actin Binding ◽  
Calponin Homology Domain ◽  
Calponin Homology ◽  
Actin Rings

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.

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