It was found that substoichiometric concentrations of cytochalasin B (CB) strongly inhibit network formation by actin filaments.

Cytochalasin B shortens actin filaments by blocking monomer addition at the fast-growing end of polymers.

It blocks adenosine-induced apoptotic body formation without affecting activation of endogenous ADP-ribosylation in leukemia HL-60 cells.

The multinucleated cells probably arise from failure of mitotic control, leading to variations in size and shape of interphase nuclei.

[7] The process by which this occurs is called pseudomitosis, which is the synchronous mitosis resulting in the division of just one nucleus.

[7] The separate nuclei are bound by a nuclear bridge and in binucleated cells the centrioles are doubled.

Another group found that CB inhibits the ability of HeLa cells to undergo cytokinesis by decomposition of the contractile ring.

[10] Research from 1971 showed that CB interferes with the release of iodine derived from thyroglobulin and blocks colloid endocytosis.

Secondly, it is possible to first form the isoindolone core in an intermolecular Diels-Alder reaction and in a second step append the macrocycle in a stepwise fashion.

[17] Cytochalasin B contains several highly polar keto- and hydroxyl groups and one peripheric lipophilic benzyl unit.

This inhibition can affect all three major steps of actin polymerization Nucleation is essential for filament build-up.

An analogue principle is used by the well-studied capping proteins which are responsible for a natural limiting factor of actin polymerization.

The hydronium ion needed to do so was produced during the activation of the sulfur atom in an earlier step.

Further metabolism leads to the formation of several smaller organic molecules such as amines (M), carbon dioxide (N) and acetic acid (O).

[26] When adding cytochalasin B and the beta-andrenergic agonist (-)-isoproterenol, prostaglandin E1 or cholera toxin to wild type S49 lymphoma cells, cAMP accumulates.

[29] Cytochalasin B can also interact with the auxin indole-3-acetic acid which occurs in wheat coleoptile segments and maize roots.

This interaction leads to the inhibition of vesicle transport and secretion of cell wall components and thereby blocks elongation and growth.

It seemed that a 2 μM concentration is sufficient in living cells to accomplish a measurable influence on the actin polymerization.

[37] Since cytochalasin B unevenly penetrates cells it promotes focal contractions of the broken cortical actin filament network by myosin.

The disorganized cortical contractions disrupt the assembly of pseudopodia which are involved in cell movement.

The nucleus then moves to the outside of the membrane, but stays connected to the cell by a thread-like cytoplasmic bridge.

[39] It has been shown that cytochalasin B binds covalently to mammalian glucose transporter proteins when irradiated with UV light.

Since mutating Trp388 and Trp412 does not completely reduce inhibition of GLUT1, it is assumed that other sites are involved in CB binding as well.

In order to do so, the effects of cytochalasin B on tumor cells by BCG (Bacillus Calmette-Guerin)-activated macrophages were examined.

A reason for this could be, that the actin filament formation, which could be important for the destruction of tumor cells by activated macrophages, is inhibited by cytochalasin B.

[47] In nature, cytochalasin B is involved in fungal virulence, food spoilage and the maintenance of the symbiosis between host and symbiont.