Control of Actin Dynamics by Allosteric Regulation of Actin Binding Proteins

2013 ◽  
pp. 1-25 ◽  
Author(s):  
Marc D.H. Hansen ◽  
Adam V. Kwiatkowski
Keyword(s):  
Binding Proteins ◽  
Allosteric Regulation ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Binding Proteins

scholarly journals STIP1/HOP Regulates the Actin Cytoskeleton through Interactions with Actin and Changes in Actin-Binding Proteins Cofilin and Profilin

2020 ◽  
Vol 21 (9) ◽  
pp. 3152 ◽  
Author(s):  
Samantha Joy Beckley ◽  
Morgan Campbell Hunter ◽  
Sarah Naulikha Kituyi ◽  
Ianthe Wingate ◽  
Abantika Chakraborty ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Binding Proteins ◽  
Major Effect ◽  
Vital Role ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Nuclear Accumulation ◽  
Actin Binding Proteins ◽  
Hsp90 Chaperone

Cell migration plays a vital role in both health and disease. It is driven by reorganization of the actin cytoskeleton, which is regulated by actin-binding proteins cofilin and profilin. Stress-inducible phosphoprotein 1 (STIP1) is a well-described co-chaperone of the Hsp90 chaperone system, and our findings identify a potential regulatory role of STIP1 in actin dynamics. We show that STIP1 can be isolated in complex with actin and Hsp90 from HEK293T cells and directly interacts with actin in vitro via the C-terminal TPR2AB-DP2 domain of STIP1, potentially due to a region spanning two putative actin-binding motifs. We found that STIP1 could stimulate the in vitro ATPase activity of actin, suggesting a potential role in the modulation of F-actin formation. Interestingly, while STIP1 depletion in HEK293T cells had no major effect on total actin levels, it led to increased nuclear accumulation of actin, disorganization of F-actin structures, and an increase and decrease in cofilin and profilin levels, respectively. This study suggests that STIP1 regulates the cytoskeleton by interacting with actin, or via regulating the ratio of proteins known to affect actin dynamics.

scholarly journals Actin-binding proteins: the long road to understanding the dynamic landscape of cellular actin networks

2016 ◽  
Vol 27 (16) ◽  
pp. 2519-2522 ◽  
Author(s):  
Pekka Lappalainen
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Filaments ◽  
Binding Proteins ◽  
Three Dimensional ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Binding Proteins ◽  
Vast Number ◽  
Actin Regulatory Proteins ◽  
The Individual

The actin cytoskeleton supports a vast number of cellular processes in nonmuscle cells. It is well established that the organization and dynamics of the actin cytoskeleton are controlled by a large array of actin-binding proteins. However, it was only 40 years ago that the first nonmuscle actin-binding protein, filamin, was identified and characterized. Filamin was shown to bind and cross-link actin filaments into higher-order structures and contribute to phagocytosis in macrophages. Subsequently many other nonmuscle actin-binding proteins were identified and characterized. These proteins regulate almost all steps of the actin filament assembly and disassembly cycles, as well as the arrangement of actin filaments into diverse three-dimensional structures. Although the individual biochemical activities of most actin-regulatory proteins are relatively well understood, knowledge of how these proteins function together in a common cytoplasm to control actin dynamics and architecture is only beginning to emerge. Furthermore, understanding how signaling pathways and mechanical cues control the activities of various actin-binding proteins in different cellular, developmental, and pathological processes will keep researchers busy for decades.

scholarly journals The Role of Actin Dynamics and Actin-Binding Proteins Expression in Epithelial-to-Mesenchymal Transition and Its Association with Cancer Progression and Evaluation of Possible Therapeutic Targets

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Magdalena Izdebska ◽  
Wioletta Zielińska ◽  
Dariusz Grzanka ◽  
Maciej Gagat
Keyword(s):  
Cancer Progression ◽  
Binding Proteins ◽  
Therapeutic Potential ◽  
Tumour Progression ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Site Formation ◽  
Actin Binding Proteins ◽  
Mesenchymal Transition

Metastasis causes death of 90% of cancer patients, so it is the most significant issue associated with cancer disease. Thus, it is no surprise that many researchers are trying to develop drugs targeting or preventing them. The secondary tumour site formation is closely related to phenomena like epithelial-to-mesenchymal and its reverse, mesenchymal-to-epithelial transition. The change of the cells’ phenotype to mesenchymal involves the acquisition of migratory potential. Cancer cells movement is possible due to the development of invasive structures like invadopodia, lamellipodia, and filopodia. These changes are dependent on the reorganization of the actin cytoskeleton. In turn, the polymerization and depolymerization of actin are controlled by actin-binding proteins. In many tumour cells, the actin and actin-associated proteins are accumulated in the cell nucleus, suggesting that it may also affect the progression of cancer by regulating gene expression. Once the cancer cell reaches a new habitat it again acquires epithelial features and thus proliferative activity. Targeting of epithelial-to-mesenchymal or/and mesenchymal-to-epithelial transitions through regulation of their main components expression may be a potential solution to the problem of metastasis. This work focuses on the role of these processes in tumour progression and the assessment of therapeutic potential of agents targeting them.

scholarly journals Identification of Arabidopsis Cyclase-associated Protein 1 as the First Nucleotide Exchange Factor for Plant Actin

2007 ◽  
Vol 18 (8) ◽  
pp. 3002-3014 ◽  
Author(s):  
Faisal Chaudhry ◽  
Christophe Guérin ◽  
Matthias von Witsch ◽  
Laurent Blanchoin ◽  
Christopher J. Staiger
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Filament ◽  
Binding Proteins ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Nucleotide Exchange ◽  
Suspension Cells ◽  
Actin Binding Proteins ◽  
Cell Shapes

The actin cytoskeleton powers organelle movements, orchestrates responses to abiotic stresses, and generates an amazing array of cell shapes. Underpinning these diverse functions of the actin cytoskeleton are several dozen accessory proteins that coordinate actin filament dynamics and construct higher-order assemblies. Many actin-binding proteins from the plant kingdom have been characterized and their function is often surprisingly distinct from mammalian and fungal counterparts. The adenylyl cyclase-associated protein (CAP) has recently been shown to be an important regulator of actin dynamics in vivo and in vitro. The disruption of actin organization in cap mutant plants indicates defects in actin dynamics or the regulated assembly and disassembly of actin subunits into filaments. Current models for actin dynamics maintain that actin-depolymerizing factor (ADF)/cofilin removes ADP–actin subunits from filament ends and that profilin recharges these monomers with ATP by enhancing nucleotide exchange and delivery of subunits onto filament barbed ends. Plant profilins, however, lack the essential ability to stimulate nucleotide exchange on actin, suggesting that there might be a missing link yet to be discovered from plants. Here, we show that Arabidopsis thaliana CAP1 (AtCAP1) is an abundant cytoplasmic protein; it is present at a 1:3 M ratio with total actin in suspension cells. AtCAP1 has equivalent affinities for ADP– and ATP–monomeric actin (Kd ∼ 1.3 μM). Binding of AtCAP1 to ATP–actin monomers inhibits polymerization, consistent with AtCAP1 being an actin sequestering protein. However, we demonstrate that AtCAP1 is the first plant protein to increase the rate of nucleotide exchange on actin. Even in the presence of ADF/cofilin, AtCAP1 can recharge actin monomers and presumably provide a polymerizable pool of subunits to profilin for addition onto filament ends. In turnover assays, plant profilin, ADF, and CAP act cooperatively to promote flux of subunits through actin filament barbed ends. Collectively, these results and our understanding of other actin-binding proteins implicate CAP1 as a central player in regulating the pool of unpolymerized ATP–actin.

scholarly journals Regulation of actin dynamics by actin-binding proteins in pollen

2010 ◽  
Vol 61 (7) ◽  
pp. 1969-1986 ◽  
Author(s):  
Christopher J. Staiger ◽  
Natalie S. Poulter ◽  
Jessica L. Henty ◽  
Vernonica E. Franklin-Tong ◽  
Laurent Blanchoin
Keyword(s):  
Binding Proteins ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Binding Proteins

Form follows function: actin-binding proteins as critical regulators of excitatory synapses

e-Neuroforum ◽  
2016 ◽  
Vol 22 (1) ◽  
Author(s):  
M.B Rust ◽  
K. Michaelsen-Preusse
Keyword(s):  
Binding Proteins ◽  
Brain Slices ◽  
Synaptic Function ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Neuronal Cultures ◽  
Excitatory Synapses ◽  
Actin Binding Proteins ◽  
Synaptic Functions ◽  
Chemical Synapses

AbstractActin filaments (F-actin) are the major structural component of excitatory synapses. In excitatory synapses, F-actin is enriched in presynaptic terminals and in dendritic spines, and actin dynamics-the spatio-temporally controlled assembly and disassembly of F-actin-have been implicated in pre- and postsynaptic physiology. Hence, actin-binding proteins that control actin dynamics emerged as important regulators of excitatory synapses linking synaptic function and structure, and therefore they are of vital importance for behavior. By the analyses of gene-targeted mice and by loss- and gain-of-function approaches in acute brain slices or dissociated neuronal cultures, studies from the last decade, including studies from our own labs, unraveled the versatile synaptic functions for members of two important families of actin dynamics regulating proteins, namely ADF/cofilin and profilin. After a short introduction into chemical synapses and actin dynamics, we will summarize and discuss recent findings on the synaptic functions of ADF/cofilin and profilin in this review article, and we will outline future directions and perspectives in the field.

scholarly journals N-terminal modification of actin by acetylation and arginylation determines the architecture and assembly rate of linear and branched actin networks

2020 ◽  
Author(s):  
Samantha M. Chin ◽  
Tomoyuki Hatano ◽  
Lavanya Sivashanmugam ◽  
Andrejus Suchenko ◽  
Anna S. Kashina ◽  
...  
Keyword(s):  
Cell Migration ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Leading Edge ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Network ◽  
Post Translational Modification ◽  
Actin Binding Proteins ◽  
N Terminus

AbstractThe great diversity in actin network architectures and dynamics is exploited by cells to drive fundamental biological processes, including cell migration, endocytosis and cell division. While it is known that this versatility is the result of the many actin-remodeling activities of actin-binding proteins, recent work implicates post-translational modification of the actin N-terminus by either acetylation or arginylation itself as an equally important regulatory mechanism. However, the molecular mechanisms by which acetylation and arginylation alter the properties of actin are not well understood. Here, we directly compare how processing, and modification of the N-terminus of actin affects its intrinsic polymerization dynamics and its remodeling by actin-binding proteins that are essential for cell migration. We find that in comparison to acetylated actin, arginylated actin reduces intrinsic as well as formin-mediated elongation and Arp2/3-mediated nucleation. By contrast, there are no significant differences in Cofilin-mediated severing. Taken together, these results suggest that cells can employ the differently modified actins to precisely regulate actin dynamics. In addition, unprocessed, or non-acetylated actin show very different effects on formin-mediated-elongation, Arp2/3-mediated nucleation, and severing by Cofilin. Altogether, this study shows that the nature of the N-terminus of actin can induce distinct actin network dynamics, which can be differentially used by cells to locally finetune actin dynamics at distinct cellular locations, such as at the leading edge.

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