Background: Jaspaklinolide is a cyclic peptide from the marine sponge Jaspis johnstoni, and harbours fungicidal and antiproliferative activity. It binds to G-actin at high affinity (15 nM) and forms actin trimeric complexes that stimulate nucleation. In vivo, it has disrupting consequences, caused by kinetic depletion of actin.
Practical usage: 0.1-1 µM inhibit auxin efflux in cell culture, growth of seedlings inhibited by 10 µM, stock solution is 2 mM in DMSO, source: Molecular Probes
Publications: Bopp et al. 1994 give the source description, Bopp et al. 2000 describe the kinetic reasons, why jaspaklinolide is acting as disrupter, Dhonukshe et al. 2008 describe the use of the drug to inhibit actin-dependent auxin transport.
Lead acetate has been used traditionally as artificial sweetener. Later it turned out to be highly toxic, among other reasons, because it paralyses muscles. Therefore it has been used to block actin filaments at a time, when cytochalasins or Latrunculin B were not available. The concentrations required to block actin by lead acetate are in the range of 50-100 mM, which shows that the action is not very specific.
In the classical work on cytoplasmic streaming in Vallisneria and Nitella, where they discovered that plants harbour actomyosin, the group of Reiko Nagai used lead acetate along with the at that time very new and not well known cytochalasins to block streaming. Since the streaming depends on stable actin cables, high concentrations (50-100 mM) over a long period (24 h) were used. However, for cytochalasin, also high concentrations were employed. It is to be expected that other actin-dependent processes are blocked at lower concentration.
Ishigami M,Nagai (1980) Motile Apparatus in Vallisneria Leaf Cells. II. Effects of Cytochalasin B and Lead Acetate on the Rate and Direction of Streaming. Cell Struct Funct 5, 13-20 - pdf
Letzte Änderung: 02.08.2011
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