Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Actin deoxyroboncuclease I interaction. Depolymerization and nucleotide exchange.

S E Hitchcock

    The Journal of Biological Chemistry
    |June 25, 1980
    PubMed
    Summary

    This study explores how DNase I interacts with actin, a protein involved in cell structure and movement. DNase I forms a complex with both globular (G-actin) and filamentous (F-actin) forms of actin. When DNase I is added to G-actin, it significantly slows down the rate at which actin exchanges its bound nucleotide. However, when DNase I is added to F-actin, it causes depolymerization and forms a complex that exchanges nucleotides much faster than the G-actin complex. The study also found that adding salt or magnesium increases the nucleotide exchange rate in G-actin-DNase I complexes. These findings suggest that DNase I may bind to F-actin before causing depolymerization, and that the structure of the actin-DNase I complex influences nucleotide exchange rates.

    Related Concept Videos

    You might also read

    Related Articles

    Articles linked to this work by shared authors, journal, and citation graph.

    Sort by
    Same author

    Study of the structure of troponin-T by measuring the relative reactivities of lysines with acetic anhydride.

    Journal of molecular biology·1981
    Same author

    Study of the structure of troponin-C by measuring the relative reactivities of lysines with acetic anhydride.

    Journal of molecular biology·1981
    Same author

    Regulation of motility in nonmuscle cells.

    The Journal of cell biology·1977
    Same author

    Depolymerization of F-actin by deoxyribonuclease I.

    Cell·1976
    Same author

    Cross-linking of troponin with dimethylimido esters.

    Biochemistry·1975
    Same author

    Study of troponin with cleavable protein crosslinkers.

    FEBS letters·1975

    Area of Science:

    • Molecular biology of actin regulation
    • Enzyme-substrate interaction dynamics
    • Structural biochemistry of nucleotide exchange

    Background:

    Actin dynamics are central to cellular processes like motility and division. Prior research has shown that actin exists in globular (G-actin) and filamentous (F-actin) forms, with nucleotide exchange influencing polymerization. It was already known that G-actin binds ATP and undergoes slow nucleotide release. However, no prior work had resolved how enzymes like DNase I might modulate actin nucleotide exchange. This gap motivated investigations into the interaction between DNase I and actin. The role of ionic strength in nucleotide exchange remained unclear. The effect of DNase I on depolymerization and nucleotide exchange had not been fully characterized. This uncertainty drove experiments to assess how DNase I affects actin structure and function. The mechanism of DNase I binding and its influence on actin conformation was previously unknown. These findings aim to clarify the biochemical interplay between actin and nucleotide-modifying enzymes.

    Purpose Of The Study:

    Keywords:
    actin regulationnucleotide bindingDNase I functionactin depolymerization

    Frequently Asked Questions

    DNase I reduces the nucleotide exchange rate in G-actin from 1.16 × 10⁻⁴ s⁻¹ to 0.28 × 10⁻⁴ s⁻¹ at 0°C.

    Adding NaCl or MgCl2 increases the nucleotide exchange rate in G-actin-DNase I complexes.

    The actin-DNase I complex formed from F-actin exchanges nucleotides 4-fold faster than G-actin complexes.

    Depolymerization is measured by monitoring the loss of viscosity when DNase I is added to F-actin.

    Related Experiment Videos

    The study aimed to investigate how DNase I interacts with actin and affects nucleotide exchange. The researchers focused on the interaction between DNase I and both G-actin and F-actin. They sought to determine whether DNase I alters the rate of nucleotide release from actin. The specific problem addressed was the mechanism by which DNase I influences actin depolymerization. The motivation stemmed from the need to understand enzyme-actin interactions in cellular regulation. The study also aimed to clarify the role of ionic strength in nucleotide exchange. Researchers wanted to compare nucleotide exchange rates in G-actin and F-actin complexes with DNase I. This work sought to provide insights into the biochemical basis of actin regulation.

    Main Methods:

    The researchers used biochemical assays to measure nucleotide exchange rates in actin-DNase I complexes. They tested the effect of DNase I on G-actin and F-actin separately. Nucleotide exchange was quantified using fluorescence or spectroscopic techniques. The experiments were conducted at 0°C to control reaction rates. The influence of ATP and ADP on exchange rates was assessed in the presence of DNase I. Ionic strength effects were studied by adding NaCl or MgCl2 to the reaction mix. The depolymerization of F-actin was monitored by measuring viscosity changes. The results were compared to baseline nucleotide exchange rates without DNase I.

    Main Results:

    DNase I reduced the nucleotide exchange rate of G-actin from 1.16 × 10⁻⁴ s⁻¹ to 0.28 × 10⁻⁴ s⁻¹ at 0°C. The presence of ATP or ADP had little effect on the exchange rate in G-actin-DNase I complexes. The actin-DNase I complex formed from F-actin showed a 4-fold faster nucleotide exchange rate than G-actin complexes. The nucleotide exchange rate in F-actin increased to 6.2 × 10⁻⁴ s⁻¹ when DNase I was added. This rate matched the depolymerization rate measured by viscosity loss. Adding NaCl or MgCl2 increased the nucleotide exchange rate in G-actin-DNase I complexes. The data suggest that DNase I binds to F-actin before dissociating monomers. These findings support a model where DNase I interacts with F-actin before depolymerization.

    Conclusions:

    The authors propose that DNase I binds to F-actin before causing depolymerization. The data suggest that the actin-DNase I complex formed from F-actin has a faster nucleotide exchange rate. This supports a model where DNase I interacts with filamentous actin first. The slower nucleotide exchange in G-actin-DNase I complexes may reflect structural differences. The effect of ionic strength on nucleotide exchange was confirmed experimentally. The presence of ATP or ADP had minimal impact on exchange rates in the presence of DNase I. These findings contribute to understanding the biochemical mechanisms of actin regulation. The study highlights the role of DNase I in modulating actin dynamics.

    The presence of ATP or ADP has little effect on the nucleotide exchange rate in actin-DNase I complexes.

    The data suggest that DNase I binds to F-actin before dissociating monomers from the filament.