The extracellular matrix (ECM) protein thrombospondin (TSP) binds specifically to polymorphonuclear leucocyte (PMN) surface receptors and promotes cell adhesion and motility. TSP receptor expression increases 30-fold after activation with the synthetic chemotactic peptide, N-formylmethionyl-leucylphenylalanine (FMLP) or the Ca2+ ionophore A23187, in combination with cytochalasin B. The expressi...

Under conditions where cytochalasin B induces ATPase activity of monomeric actin (0.3 mM MgCl2, 1 mM EGTA, 30 microns cytochalasin B, 1 mM ATP) the rate constant of the exchange of actin-bound epsilon-ATP for free ATP is about 4-6 times faster than steady state ATPase activity. When a stoichiometric ATP-actin complex is extracted with PCA (single turnover experiment) the apparent rate constant ...

Cytochalasin B, a metabolic product of several fungi, enhances up to 10-fold the sensitivity and reactivity of human leukocytes to antigen E or anti-IgE-mediated histamine release. The effect of cytochalasin B is a result of its action on the second, antigen-independent, stage of histamine release. These data suggest that normally, antigen-triggered histamine release is modulated by a cytochala...

In cynomolgus monkeys, intracameral infusion of 0.2 to 5.0 mug of cytochalasin B caused an increase in outflow facility, as measured by two-level constant pressure perfusion. Cytochalasin B had its full effect in eyes which had undergone surgical disinsertion of the ciliary muscle from the scleral spur, and were therefore insensitive to pilocarpine. The cytochalasin effect was apparent in less ...

Actin microfilaments transmit traction and contraction forces generated within a cell to the extracellular matrix during embryonic development, wound healing and cell motility, and to maintain tissue structure and tone. Therefore, the state of the actin cytoskeleton strongly influences the mechanical properties of cells and tissues. Cytochalasin D and Latrunculin are commonly used reagents that...

Friend erythroleukemia cells grown in culture and induced to differentiate along the erythroid developmental pathway by dimethyl sulfoxide (DMSO) were used as a model system to investigate the requirement for cellular replication to express a differentiated erythroid phenotype. That cytokinesis is not essential for DMSO-induced erythroid differentiation as measured by the synthesis and accumula...

Villin is an actin-binding protein that is associated with the cytoskeleton of brush border microvilli. In vitro, villin nucleates, caps or severs actin filaments in a Ca(2+)-dependent manner. In the absence of Ca2+, villin organizes microfilaments into bundles. Transfection of a villin-specific cDNA into cultured cells that do not produce this protein results in the growth of long surface micr...