Phallotoxins bind to actins

Wieland, Th.; Govindan, V. M.

doi:10.1016/0014-5793(74)80404-7

Cited by 57 publications

(22 citation statements)

References 5 publications

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“…The observations presented here, taken together with the established effects of phallotoxins (38,39) and cytochalasins (11,12,15,22) on actin in vitro, suggest a hypothesis for the mode of CB inhibition of cytoplasmic streaming in characean algae . We propose that CB inhibits streaming by causing a net release of actin monomers and/or oligomers from the subcortical actin bundles into the endoplasm.…”

Section: Discussionmentioning

confidence: 53%

Fluorescence studies on modes of cytochalasin B and phallotoxin action on cytoplasmic streaming in Chara.

Nothnagel¹,

Barak²,

Sanger³

et al. 1981

The Journal of Cell Biology

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Various investigations have suggested that cytoplasmic streaming in characean algae is driven by interaction between subcortical actin bundles and endoplasmic myosin . To further test this hypothesis, we have perfused cytotoxic actin-binding drugs and fluorescent actin labels into the cytoplasm of streaming Chara cells. Confirming earlier work, we find that cytochalasin B (CB) reversibly inhibits streaming. In direct contrast to earlier investigators, who have found phalloidin to be a potent inhibitor of movement in amoeba, slime mold, and fibroblastic cells, we find that phalloidin does not inhibit streaming in Chara but does modify the inhibitory effect of CB . Use of two fluorescent actin probes, fluorescein isothiocyanateheavy meromyosin (FITC-HMM) and nitrobenzoxadiazole-phalIacid in (NBD-Ph), has permitted visualization of the effects of CB and phalloidin on the actin bundles. FITC-HMM labeling in perfused but nonstreaming cells has revealed a previously unobserved alteration of the actin bundles by CB . Phalloidin alone does not perceptibly alter the actin bundles but does block the alteration by CB if applied as a pretreatment . NBD-Ph perfused into the cytoplasm of streaming cells stains actin bundles without inhibiting streaming. NBD-Ph staining of actin bundles is not initially observed in cells inhibited by CB but does appear simultaneously with the recovery of streaming as CB leaks from the cells. The observations reported here are consistent with the established effects of phallotoxins and CB on actin in vitro and support the hypothesis that streaming is generated by actin-myosin interactions .The highly organized cytoplasmic streaming exhibited by the giant internodal cells of characean algae has long made these cells an attractive system for the study of cell motility (4) . Accumulated evidence has suggested that motility in a variety of eukaryotic cells is actomyosin-dependent (21) . Measurements of streaming-velocity profiles in characean cells have suggested that the motive force is generated primarily at the interface between the stationary ectoplasm and motile endoplasm (17) . Early ultrastructural studies have revealed the presence of microfilament bundles attached to the chloroplasts at this interface (26) . Subsequent electron and, more recently, fluorescence microscope studies using labeling by heavy meromyosin (20, 27, 29) or antiactin antibodies (45) have demonstrated the presence of actin in these subcortical microfilament bundles and established the unidirectional orientation of the actin filaments (19) . Other light microscope studies have suggested the presence of endoplasmic filaments that appeared to branch from the subcortical actin bundles and participate in the generation of the motive force (1, 2) .The demonstration of actin in characean cells has encouraged workers to search for evidence of myosin in these cells as well . Using a perfusion technique that permitted manipulation of internal pH and ion and ATP concentrations, Williamson observed the ATP-dependent moti...

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Section: Discussionmentioning

confidence: 53%

Fluorescence studies on modes of cytochalasin B and phallotoxin action on cytoplasmic streaming in Chara.

Nothnagel¹,

Barak²,

Sanger³

et al. 1981

The Journal of Cell Biology

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“…The aim of the present paper is to analyse the display of major cytoskeletal proteins tubulin and actin during mating using fluorescent staining with the monoclonal antibody TuOl for atubulin (Viklickjr et al, 1982Drhber et al, 1985 and rhodamine-conjugated phalloidin for Factin (Wieland & Govindan, 1974). We have concentrated on relevant features concerned with the topology of the cytoskeleton in the following events: (i) polarization of gametic cells induced under the influence of mating pheromones, (ii) cell fusion of appropriate mating partners, (iii) fusion of parental nuclei within zygotes, (iv) positioning of dividing nuclei within zygotes, and (v) development of zygotic buds.…”

Section: Introductionmentioning

confidence: 99%

Tubulin and Actin Topology during Zygote Formation of Saccharomyces cerevisiae

Hašek

Rupeš²,

Svobodová³

et al. 1987

Microbiology

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The topology of tubulin and actin during mating of Saccharomyces cerevisiae was analysed by fluorescence microscopy with the monoclonal anti-tubulin antibody Tu01 and rhodamine-labelled phalloidin. Preconjugatory cells displayed an asymmetric distribution of the microtubule and actin cytoskeleton and an overall polarization of the cells preceding cell fusion. Prior to karyogamy, the haploid spindle pole bodies were associated with abundant cytoplasmic microtubules. Budding zygotes revealed the same tubulin and actin patterns as vegetative cells. Treatment of the mating mixture with the microtubule inhibitor nocodazole (10 micrograms ml-1) did not prevent polarization and fusion of haploids, zygote formation and emergence of the first zygotic bud. In marked contrast, the migration of the nucleus in preconjugatory cells as well as nuclear migration and fusion within the zygotes was unequivocally blocked by the action of the drug. It is suggested that the problem of the morphogenesis of mating should be approached by considering interactions at the cell periphery.

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“…Phallotoxins bind to actin [13,14]. As determined with the derivative, rhodamine-phalloidin, the toxins bind to actin filaments with a 1 : 1 stoichiometry [15]: We have studied the ATPase activity related to actin polymer formation under various conditions in the absence and presence of phalloidin derivatives.…”

Section: Introductionmentioning

confidence: 99%

The effect on actin ATPase of phalloidin and tetramethylrhodamine phalloidin

Пинаев¹,

Schutt²,

Lindberg³

1995

FEBS Letters

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Actin polymerization has been studied in the absence of excess nucleotide. Using G-actin ATP monomers, it was shown that mechanical shearing stimulates ATP hydrolysis. The procedures used enabled the detection of differential effects of phalloidin and tetramethylrhodamine-phalloidin, on the Prrelease step of the actin ATPase. It is concluded that tetramethylrhodamine, in contrast to phaHoidin, accelerates Prrelease from actin filaments.

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Phallotoxins bind to actins

Cited by 57 publications

References 5 publications

Fluorescence studies on modes of cytochalasin B and phallotoxin action on cytoplasmic streaming in Chara.

Fluorescence studies on modes of cytochalasin B and phallotoxin action on cytoplasmic streaming in Chara.

Tubulin and Actin Topology during Zygote Formation of Saccharomyces cerevisiae

The effect on actin ATPase of phalloidin and tetramethylrhodamine phalloidin

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