The introduction of chemical inhibitors into living cells at specific times in development is a useful method for investigating the roles of specific proteins or cytoskeletal components in developmental processes. Some embryos, such as those of Caenorhabditis elegans, however, possess a tough eggshell that makes introducing drugs and other molecules into embryonic cells challenging. We have dev...

An antiparallel actin dimer has been proposed to be an intermediate species during actin filament nucleation. We now show that latrunculin A, a marine natural product that inhibits actin polymerization, arrests polylysine-induced nucleation at the level of an antiparallel dimer, resulting in its accumulation. These dimers, when composed of pyrene-labeled actin subunits, give rise to a fluoresce...

As part of the cytoskeleton, actin is essential for the morphology, motility, and division of eukaryotic cells. Recent X-ray fiber diffraction studies have shown that the conformation of monomeric actin is flattened upon incorporation into the filament by a relative rotation of its two major domains. The antiproliferative activity of latrunculin, a macrolide toxin produced by sponges, seems to ...

T cell receptor (TCR) signaling is initiated and sustained in microclusters; however, it's not known whether signaling also occurs in the TCR-rich central supramolecular activation cluster (cSMAC). We showed that the cSMAC formed by fusion of microclusters contained more CD45 than microclusters and is a site enriched in lysobisphosphatidic acid, a lipid involved in sorting ubiquitinated membran...

Latrunculin-B (LAT-B), a macrolide derived from the marine sponge Latrunculia magnifica, sequesters monomeric G-actin, leading to the disassembly of actin filaments in cultured cells. In this study, we determined the effect of LAT-B on outflow facility in living monkeys. Total outflow facility was measured by 2-level constant pressure perfusion of the anterior chamber (AC) before and immediatel...

In cultured chick ciliary neurons, when ATP synthesis is inhibited, ATP depletion is reduced approximately 50% by slowing actin filament turnover with jasplakinolide or latrunculin A. Jasplakinolide inhibits actin disassembly, and latrunculin A prevents actin assembly by sequestering actin monomers. Cytochalasin D, which allows assembly-disassembly, but only at pointed ends, is less effective i...

It is believed that de novo protein synthesis is fundamentally linked to synaptic changes in neuronal circuits involved in acquisition and extinction of conditioned responses. Recent studies show that neuronal plasticity may be also altered by cytoskeletal rearrangement independently of protein synthesis. We investigated the role of these processes in the hippocampus during acquisition and exti...