Interaction Of Cytochalasin Research Articles

Morphological studies of living cells using gold nanoparticles and dark-field optical section microscopy

The morphologic changes of living cells under drug interactions were studied by using 80-nm gold nanoparticles and dark-field optical section microscopy. The gold nanoparticles were coated with poly (L-lysine), which attached to the membranes of various cells by way of electrostatic attractive force. A three-dimensional (3-D) morphological image was obtained by measuring the peak scattering intensities of gold nanoparticles at different focal planes. An algorithm for the reconstruction of 3-D cell morphology was presented. With the measured nanoparticle images and calculations, we show morphologic changes of lung cancer cells under the interaction of cytochalasin D drug at different times.

Immobilized Proteoliposome Affinity Chromatography for Quantitative Analysis of Specific Interactions between Solutes and Membrane Proteins. Interaction of Cytochalasin B and d-Glucose with the Glucose Transporter Glut1

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionImmobilized Proteoliposome Affinity Chromatography for Quantitative Analysis of Specific Interactions between Solutes and Membrane Proteins. Interaction of Cytochalasin B and d-Glucose with the Glucose Transporter Glut1Qing Yang and Per LundahlCite this: Biochemistry 1996, 35, 33, 11012Publication Date (Web):August 20, 1996Publication History Published online20 August 1996Published inissue 1 January 1996https://doi.org/10.1021/bi965011cCopyright © 1996 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views141Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (28 KB) Get e-Alerts Get e-Alerts

Immobilized proteoliposome affinity chromatography for quantitative analysis of specific interactions between solutes and membrane proteins. Interaction of cytochalasin B and D-glucose with the glucose transporter Glut1.

An affinity gel bed was prepared by reconstitution of a transmembrane protein, the human red cell glucose transporter (Glut1), followed by steric immobilization of the proteoliposomes in small and rigid gel beads by freeze-thawing. The specific interactions between the reconstituted Glut1, the transport inhibitor cytochalasin B (CB), and the transported solute D-glucose were analyzed by isocratic chromatography of CB on the Glut1-proteoliposome gel bed. Specific retardation of CB which decreased upon inclusion of the competitor D-glucose in the eluent was observed on-line. The equilibrium constants for CB and D-glucose interaction with Glut1 (Kd 1.5 x 10(-7) M and 67 mM, respectively) obtained by use of equations derived for the affinity chromatographic analysis were consistent with values obtained by others by conventional methods. Effects of liposome composition, pH, and time on the CB binding activity of Glut1 were studied. Reconstitution of a membrane protein into a lipid environment and steric immobilization of the proteoliposomes favor retention of the protein activity. Immobilized proteoliposome affinity chromatography (IPAC) is a novel, powerful method for analysis of interactions between membrane proteins and solutes.

Interaction of cytochalasin D with actin filaments in the presence of ADP and ATP.

Cytochalasin D strongly inhibits the faster components in the reactions of actin filament depolymerization and elongation in the presence of 10 mM Tris-Cl-, pH 7.8, 0.2 mM dithiothreitol, 1 mM MgCl2, 0.1 mM CaCl2, and 0.2 mM ATP or ADP. Assuming an exclusive and total capping of the barbed end by the drug, the kinetic parameters derived at saturation by cytochalasin D refer to the pointed end and are 10-15-fold lower than at the barbed end. In ATP, the critical concentration increases with cytochalasin D up to 12-fold its value when both ends are free; as a result of the lowering of the free energy of nucleation by cytochalasin D, short oligomers of F-actin exist just above and below the critical concentration. Cytochalasin D interacts strongly with the barbed ends independently of the ADP-G-actin concentration (K = 0.5 nM-1). In contrast, the affinity of cytochalasin D decreases cooperatively with increasing ATP-G-actin concentration. These data are equally well accounted for by two different models: either cytochalasin D binds very poorly to ATP-capped filament ends whose proportion increases with actin concentration, or cytochalasin D binds equally well to ATP-ends and ADP-ends and also binds to actin dimers in ATP but not in ADP. A linear actin concentration dependence of the rate of growth was found at the pointed end, consistent with the virtual absence of an ATP cap at that end.

Interaction of cytochalasin B with actin filaments nucleated or fragmented by villin.

Villin, a 95,000-dalton protein, is a major component of microvillus cores isolated from intestinal brush borders. In this study, we compared the Ca2+-dependent action of this protein on actin filaments with that of cytochalasin B, a fungal metabolite that binds to the "barbed" end of actin filaments and nuclei. We found that substoichiometric levels of villin inhibit actin filament elongation and self-association in a cytochalasin-like manner. In addition, the protein releases membrane-bound F-actin in the absence of high shear force, probably by severing the filaments. The filament fragments formed in the presence of villin, as well as a nucleating complex consisting of villin and actin, bind stoichiometric amounts of [3H]cytochalasin B with high affinity. The results of this study indicate that both villin and cytochalasin B bind to the same end of actin filaments, yet differ in their binding sites.

On the molecular basis of action of cytochalasin B.

AbstractTritium‐labeled cytochalasin B binds rapidly and reversibly to mammalian cells, and a class of high‐affinity sites (Kn ≅ 10−7 M) and a class of low‐affinity sites (KD ⩾ 10−5 M) are detected. In red blood cells, the high‐affinity binding sites (about 3 × 105 per cell) are associated with the plasma membrane, and at least 80% of these appear to be intimately related to the glucose transport system. Fractionation of cellular components of platelets by differential centrifugation and gel filtration chromatography reveals that the high‐affinity binding sites in these cells are also associated with membranous materials. A substantial number of the low‐affinity binding sites can be traced to platelet actin. The binding of cytochalasin B to actin is consistent with the alteration of intrinsic viscosity and morphology of actin filaments in vitro by the compound at concentrations of around 10−5‐10−4 M. The interaction of cytochalasin B with actin may account for its inhibitory effect on various forms of cell motility.

Interaction of cytochalasin B and actomyosin

Interaction of cytochalasin B and actomyosin