scholarly journals Structure and Mechanism of Mouse Cyclase-associated Protein (CAP1) in Regulating Actin Dynamics

2014 ◽  
Vol 289 (44) ◽  
pp. 30732-30742 ◽  
Author(s):  
Silvia Jansen ◽  
Agnieszka Collins ◽  
Leslie Golden ◽  
Olga Sokolova ◽  
Bruce L. Goode
Keyword(s):  
Plant Species ◽  
Structure And Function ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Nucleotide Exchange ◽  
Actin Turnover ◽  
Actin Structure ◽  
Wh2 Domain ◽  
And Function ◽  
Β Sheet

Srv2/CAP is a conserved actin-binding protein with important roles in driving cellular actin dynamics in diverse animal, fungal, and plant species. However, there have been conflicting reports about whether the activities of Srv2/CAP are conserved, particularly between yeast and mammalian homologs. Yeast Srv2 has two distinct functions in actin turnover: its hexameric N-terminal-half enhances cofilin-mediated severing of filaments, while its C-terminal-half catalyzes dissociation of cofilin from ADP-actin monomers and stimulates nucleotide exchange. Here, we dissected the structure and function of mouse CAP1 to better understand its mechanistic relationship to yeast Srv2. Although CAP1 has a shorter N-terminal oligomerization sequence compared with Srv2, we find that the N-terminal-half of CAP1 (N-CAP1) forms hexameric structures with six protrusions, similar to N-Srv2. Further, N-CAP1 autonomously binds to F-actin and decorates the sides and ends of filaments, altering F-actin structure and enhancing cofilin-mediated severing. These activities depend on conserved surface residues on the helical-folded domain. Moreover, N-CAP1 enhances yeast cofilin-mediated severing, and conversely, yeast N-Srv2 enhances human cofilin-mediated severing, highlighting the mechanistic conservation between yeast and mammals. Further, we demonstrate that the C-terminal actin-binding β-sheet domain of CAP1 is sufficient to catalyze nucleotide-exchange of ADP-actin monomers, while in the presence of cofilin this activity additionally requires the WH2 domain. Thus, the structures, activities, and mechanisms of mouse and yeast Srv2/CAP homologs are remarkably well conserved, suggesting that the same activities and mechanisms underlie many of the diverse actin-based functions ascribed to Srv2/CAP homologs in different organisms.

scholarly journals A Comparison between Vanadyl, Vanadate, and Decavanadate Effects in Actin Structure and Function: Combination of Several Spectroscopic Studies

2012 ◽  
Vol 27 ◽  
pp. 355-359 ◽  
Author(s):  
S. Ramos ◽  
J. J. G. Moura ◽  
M. Aureliano
Keyword(s):  
Actin Polymerization ◽  
Hydrophobic Surface ◽  
Spectroscopic Studies ◽  
Structure And Function ◽  
Actin Binding ◽  
Cysteine Oxidation ◽  
Natural Ligand ◽  
Function Combination ◽  
Actin Structure ◽  
And Function

The studies about the interaction of actin with vanadium are seldom. In the present paper the effects of vanadyl, vanadate, and decavanadate in the actin structure and function were compared. Decavanadate clearly interacts with actin, as shown byV51-NMR spectroscopy. Decavanadate interaction with actin induces protein cysteine oxidation and vanadyl formation, being both prevented by the natural ligand of the protein, ATP. Monomeric actin (G-actin) titration with vanadyl, as analysed by EPR spectroscopy, indicates a 1 : 1 binding stoichiometry and akdof 7.5 μM. Both decavanadate and vanadyl inhibited G-actin polymerization into actin filaments (F-actin), with aIC50of 68 and 300 μM, respectively, as analysed by light-scattering assays. However, only vanadyl induces G-actin intrinsic fluorescence quenching, which suggests the presence of vanadyl high-affinity actin-binding sites. Decavanadate increases (2.6-fold) actin hydrophobic surface, evaluated using the ANSA probe, whereas vanadyl decreases it (15%). Finally, both vanadium species increasedε-ATP exchange rate (k=6.5×10−3and4.47×10−3 s−1for decavanadate and vanadyl, resp.). Putting it all together, it is suggested that actin, which is involved in many cellular processes, might be a potential target not only for decavanadate but above all for vanadyl.

scholarly journals Actin Structure and Function: What We Still Do Not Understand

2007 ◽  
Vol 282 (50) ◽  
pp. 36133-36137 ◽  
Author(s):  
Emil Reisler ◽  
Edward H. Egelman
Keyword(s):  
Structure And Function ◽  
Actin Structure ◽  
And Function

scholarly journals Cobl-like promotes actin filament formation and dendritic branching using only a single WH2 domain

2017 ◽  
Vol 217 (1) ◽  
pp. 211-230 ◽  
Author(s):  
Maryam Izadi ◽  
Dirk Schlobinski ◽  
Maria Lahr ◽  
Lukas Schwintzer ◽  
Britta Qualmann ◽  
...  
Keyword(s):  
Actin Filament ◽  
Cell Biology ◽  
Network Formation ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Filament Formation ◽  
Uncharacterized Protein ◽  
Dendritic Branching ◽  
Wh2 Domain ◽  
Actin Nucleator

Local actin filament formation powers the development of the signal-receiving arbor of neurons that underlies neuronal network formation. Yet, little is known about the molecules that drive these processes and may functionally connect them to the transient calcium pulses observed in restricted areas in the forming dendritic arbor. Here we demonstrate that Cordon-Bleu (Cobl)–like, an uncharacterized protein suggested to represent a very distantly related, evolutionary ancestor of the actin nucleator Cobl, despite having only a single G-actin–binding Wiskott–Aldrich syndrome protein Homology 2 (WH2) domain, massively promoted the formation of F-actin–rich membrane ruffles of COS-7 cells and of dendritic branches of neurons. Cobl-like hereby integrates WH2 domain functions with those of the F-actin–binding protein Abp1. Cobl-like–mediated dendritic branching is dependent on Abp1 as well as on Ca2+/calmodulin (CaM) signaling and CaM association. Calcium signaling leads to a promotion of complex formation with Cobl-like’s cofactor Abp1. Thus, Ca2+/CaM control of actin dynamics seems to be a much more broadly used principle in cell biology than previously thought.

scholarly journals The role of strand 1 of the C β-sheet in the structure and function of α1-antitrypsin

2009 ◽  
Vol 10 (12) ◽  
pp. 2518-2524 ◽  
Author(s):  
Stephen P. Bottomley ◽  
Isobel D. Lawrenson ◽  
Deborah Tew ◽  
Weiwen Dai ◽  
James C. Whisstock ◽  
...  
Keyword(s):  
Structure And Function ◽  
And Function ◽  
Β Sheet

scholarly journals The Dynamic of Pekarangan Selahuni 2 Homlet, Ciomas Rahayu Village, Bogor

2020 ◽  
Vol 10 (3) ◽  
pp. 364-373
Author(s):  
Muhammad Saddam Ali ◽  
Hadi Susilo Arifin ◽  
Nurhayati H.S. Arifin
Keyword(s):  
Plant Species ◽  
Ornamental Plants ◽  
Structure And Function ◽  
Ornamental Plant ◽  
Average Area ◽  
The Past ◽  
Main Factors ◽  
And Function

Urbanization and fragmentation are the main factors causing dynamics in the pekarangan. The dynamics that occur are related to the structure and function of the pekarangan. This makes the pekarangan performance changes according to the interference of the pekarangan owner. Selahuni 2 Homlet, Ciomas Rahayu Village, Bogor has become the location for observing the dynamics of the past two decades. Pekarangan samples taken in 2019 are exactly the same as those taken in 1998 and 2007, totaling 10 houses. The aim is to determine the extent of changes that occur in the pekarangan, both structure and function. Measuring the area, ownership of the pekarangan, recording of species and function of the existing vegetation of the pekarangan. In 2019, data on ownership of houses and pekarangans by old owners dropped dramatically by only 40%. In 2019, the average pekarangan area will decrease by an average area of 110.81 m2. In 1998, 2007 and 2019, the percentage of the number of non-ornamental plant species was 4-10% higher than that of ornamental plants. Therefore, there was a change in both the extent and ownership, function and structure of the vegetation in the Selahuni 2 Homlet’s pekarangan which was caused by urbanization and fragmentation factors.

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