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 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 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 Actin-binding compounds, discovered by FRET-based high-throughput screening, differentially affect skeletal and cardiac muscle

2020 ◽  
Author(s):  
Piyali Guhathakurta ◽  
Lien A. Phung ◽  
Ewa Prochniewicz ◽  
Sarah Lichtenberger ◽  
Anna Wilson ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Striated Muscle ◽  
Muscle Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Structure And Function ◽  
Actin Binding ◽  
Myosin Isoforms ◽  
And Function

AbstractWe have used spectroscopic and functional assays to evaluate the effects of a group of actin-binding compounds on striated muscle protein structure and function. Actin is present in every human cell, and its interaction with multiple myosin isoforms and multiple actin-binding proteins is essential for cellular viability. A previous high-throughput time-resolved fluorescence resonance energy transfer (TR-FRET) assay from our group identified a class of compounds that bind to actin and affect actomyosin structure and function. In the current study, we tested their effects on the two isoforms of striated muscle α-actins, skeletal and cardiac. We found that a majority of these compounds affected the transition of monomeric G-actin to filamentous F-actin, and that these effects were different for the two actin isoforms, suggesting a different mode of action. To determine the effects of these compounds on sarcomeric function, we further tested their activity on skeletal and cardiac myofibrils. We found that several compounds affected ATPase activity of skeletal and cardiac myofibrils differently, suggesting different mechanisms of action of these compounds for the two muscle types. We conclude that these structural and biochemical assays can be used to identify actin-binding compounds that differentially affect skeletal and cardiac muscles. The results of this study set the stage for screening of large chemical libraries for discovery of novel compounds that act therapeutically and specifically on cardiac or skeletal muscle.

Dictyostelium discoideum contains two profilin isoforms that differ in structure and function

1991 ◽  
Vol 100 (3) ◽  
pp. 481-489 ◽  
Author(s):  
M. Haugwitz ◽  
A.A. Noegel ◽  
D. Rieger ◽  
F. Lottspeich ◽  
M. Schleicher
Keyword(s):  
Amino Acid ◽  
Cdna Library ◽  
Dictyostelium Discoideum ◽  
Actin Polymerization ◽  
Critical Concentration ◽  
Exchange Chromatography ◽  
Amino Acid Sequences ◽  
Actin Binding ◽  
Gene Coding ◽  
And Function

Two profilin isoforms (profilins I and II) have been purified from Dictyostelium discoideum, using affinity chromatography on a poly(L-proline) matrix; the isoforms could be separated by cation-exchange chromatography on a FPLC system. The gene coding for profilin I was cloned from a lambda gt11 cDNA library using a profilin I-specific monoclonal antibody. The profilin II cDNA was isolated by probing the cDNA library with an oligonucleotide deduced from the N-terminal amino acid sequence of profilin II, which has an open N terminus in contrast to profilin I. The deduced amino acid sequences of both genes show that profilin I in comparison to profilin II is slightly larger (13,064 Da vs 12,729 Da), has a more acidic isoelectric point (calc. pI 6.62 vs 7.26) and shares with profilin II 68 identical residues out of 126 amino acids. Although both profilins contain a conserved lysine residue in the putative actin-binding region and can be crosslinked covalently to G-actin, the crosslinking efficiency of profilin II to actin is substantially higher than that of profilin I. These data are in agreement with studies on the functional properties of the profilin isoforms. In most preparations profilin II was more efficient in delaying the onset of elongation during the course of actin polymerization and caused a higher critical concentration for actin polymerization than profilin I, probably due to the slightly increased affinity of profilin II for D. discoideum G-actin (approx. Kd 1.8 × 10(−6) M) as compared to that of profilin I (approx. Kd 5.1 × 10(−6) M).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals High-throughput screen, using time-resolved FRET, yields actin-binding compounds that modulate actin–myosin structure and function

2018 ◽  
Vol 293 (31) ◽  
pp. 12288-12298 ◽  
Author(s):  
Piyali Guhathakurta ◽  
Ewa Prochniewicz ◽  
Benjamin D. Grant ◽  
Kurt C. Peterson ◽  
David D. Thomas
Keyword(s):  
High Throughput ◽  
Structure And Function ◽  
Actin Binding ◽  
High Throughput Screen ◽  
Time Resolved ◽  
And Function

Fluorescence Spectroscopic Studies on Structure and Function of Lipolytic Enzymes

2001 ◽  
pp. 63-74
Author(s):  
Albin Hermetter ◽  
Birgit Mayer ◽  
Hubert Scholze ◽  
Elfriede Zenzmaier ◽  
Marion Graupner
Keyword(s):  
Spectroscopic Studies ◽  
Structure And Function ◽  
Lipolytic Enzymes ◽  
And Function
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