Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Taylor, D. Lansing; Wang, Y L; Heiple, J M

doi:10.1083/jcb.86.2.590

Cited by 94 publications

(59 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One explanation derived from recent studies identified an AMPS synthetase activity in muscle and showed that the enzyme binds to F-actin specifically (20). Whether or not these results can be used to infer a role for actin in the pinocytotic activity of D. discoideum, as suggested by studies with other systems (24), remains to be shown.…”

Section: Discussionmentioning

confidence: 98%

Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

Ef¹,

Jahngen²,

Varnum³

et al. 1981

The Journal of Cell Biology

View full text Add to dashboard Cite

In the present study we examine the effects of the drug hadacidin (N-formyl-Nhydroxyglycine) on pinocytosis in the eucaryotic microorganism Dictyostelium discoideum . At concentrations of up to -8 mg/ml, hadacidin inhibited the rate of pinocytosis of fluorescein isothiocyanate (FITC) dextran in cells in growth medium in a concentration-dependent manner but had no effect on cells in starvation medium.Because hadacidin also inhibits cellular proliferation at this concentration, the relationship between growth rate and pinocytosis was studied further using another drug, cerulenin, to produce growth-arrest . These experiments showed no changes in the rate of pinocytosis even after complete cessation of cellular proliferation .Other studies showed that the transfer of cells from growth to starvation medium reduced the rate of pinocytosis by -50%. A reduction of similar magnitude occurred if cells were transferred from growth to starvation medium containing hadacidin . Also, no additional reduction in pinocytosis occurred when cells that had been treated with hadacidin were transferred to starvation medium containing hadacidin . These cells were able to take up ["C]hadacidin in the starvation medium .In contrast to the results with had acid in-treated cells, cells in a cerulenin-induced state of growth-arrest when transferred to starvation medium exhibited the same 50% reduction in pinocytosis observed in cells not previously exposed to either drug. Cells treated with azide, in either growth or starvation medium, exhibited an immediate inhibition of all pinocytotic activity .After the transfer of log-phase cells to starvation medium supplemented with glucose, the reduction in rate was only -10-15% . In contrast, a 50% reduction was observed after supplementation of starvation medium with sucrose, KCI, or concanavalin A. Maintaining the cells in growth medium containing hadacidin for as long as 16 h had no effect on the rate at which the cells aggregated .These results are consistent with the conclusion that D . discoideum exhibits two types of pinocytotic activity : one that is nutrient dependent and the other independent of nutrients . This latter activity persists in starvation medium and is unaffected by hadacidin, whereas the nutrient-dependent activity is present in growth medium and is inhibited by hadacidin .The amino acid analogue hadacidin (N-formylhydroxyaminoacetic acid), originally a fungal isolate

show abstract

Section: Discussionmentioning

confidence: 98%

Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

Ef¹,

Jahngen²,

Varnum³

et al. 1981

The Journal of Cell Biology

View full text Add to dashboard Cite

show abstract

“…We have also initiated an integration of the available facts on primary messengers, membrane prop-erties, secondary messengers, and contractile events involved in stimulated motile processes. These studies and the accompanying paper (72) further indicate the value of the giant freeliving amebas for studying basic cellular processes. Preliminary reports of this work have appeared in abstract form (67, 71).2…”

mentioning

confidence: 99%

“…Damaging the plasmalemma and underlying cortex has been shown to induce a wound-healing contraction of the cortical actin and myosin (35,72) . Damaging the aequorin-injected cells in Marshall's solution by micropuncture resulted in intense localized increases in luminescence at the sites of damage that spread only a few microns from the wounds (Fig .…”

Section: Stimulated Pulses Of Luminescencementioning

confidence: 99%

“…A piezoelectric vibrator was also used to stimulate cells with vibrations conducted through the medium (57) . Capping of Con A on the cell surface was induced as described in the accompanying paper (72). Pinocytosis was induced by rinsing the cells with the Alcian blue solution .…”

mentioning

confidence: 99%

“…Pinocytotic channels formed within a few minutes (39) . Phalloidin at a final concentration of -10-' M was injected into cells previously injected with aequorin (72) . This study represents experiments performed on more than 50 separate cells .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Contractile basis of ameboid movement. VII. Aequorin luminescence during ameboid movement, endocytosis, and capping.

Taylor¹,

Blinks²,

Reynolds³

1980

The Journal of Cell Biology

Self Cite

127

View full text Add to dashboard Cite

Aequorin luminescence has been utilized to determine the spatial and temporal fluctuations of the free calcium ion concentration [Ca"] in Chaos carolinensis during ameboid movement, pinocytosis, and capping. The [Ca"] increases above _10-7 M during normal ameboid movement . Three types of luminescent signals are detected in cells: continuous luminescence, spontaneous pulses, and stimulated pulses . Continuous luminescence is localized in the tails of actively motile cells, and spontaneous pulses occur primarily over the anterior regions of cells. We are sometimes able to correlate the spontaneous pulses with extending pseudopods, whereas stimulated pulses are induced by mechanical damage, electrical stimulation, concanavalin A-induced capping, and pinocytosis. The localization of both distinct actin structures and sites where [Ca"] increases suggests cellular sites of contractile activity . The independent evidence from localizing actin structures and the distribution of [Ca"] can also be viewed in relation to the solation-contraction coupling hypothesis defined in vitro.Calcium regulation of cytoplasmic structure and contractility in ameboid cells was first identified in single cell models from Chaos carolinensis (66) . The calcium regulation of both gelation and contraction was subsequently described in bulk cell-free extracts (21, 68, 69), in partially reconstituted models (31), and in single living cells (70) . Recently, a high-affinity calciumbinding protein which regulates gelation and plays a role in regulating contraction (77) (see references 73 and 74 for reviews) has been isolated from Dictyostelium discoideum . Evidence for calcium regulation of cytoplasmic structure and/or contractility has also been demonstrated in cell models from other ameboid cells, including Acanthamoeba (50), Ehrlich tumor cells (45), and macrophages (78). In addition, a great deal of indirect evidence has also supported the suggestion that calcium regulates at least some of the events involved in ameboid movements (see references 33 and 74 for reviews) .A direct identification of fluctuations in the free calcium ion concentration in living cells is necessary to identify calcium as a physiologically relevant intracellular messenger involved in cell motility . This is especially true because other parameters, including changes in pH, can also affect cytoplasmic structure THE JOURNAL of CELT BIOLOGY -VOLUmE 86 AUGUST 1980 599-607 ©The Rockefeller University Press -0021-9525/80/08/0599/09 $1 .00 and contractility in vitro (21, 68, 69).' Ultimately, a map of the spatial and temporal distribution of all potential regulatory factors must be constructed and correlated with motile behavior in living cells.Aequorin luminescence (9-11, 56, 60, 61) has been used as a highly sensitive indicator of intracellular free calcium in several types of cells (see references 9, 10 and 56 for reviews) . The high signal to noise ratio, relative specificity for Ca", lack of toxicity, and ease of signal detection have made this technique attr...

show abstract

Intracellular pressure is a motive force for cell motion inAmoeba proteus

Yanai

Kenyon

Butler

et al. 1996

Cell Motil. Cytoskeleton

View full text Add to dashboard Cite

The cortical filament layer of free‐living amoebae contains concentrated actomyosin, suggesting that it can contract and produce an internal hydrostatic pressure. We report here on direct and dynamic intracellular pressure (Pic) measurements in Amoeba proteus made using the servo‐null technique. In resting apolar A. proteus, Pic increased while the cells remained immobile and at apparently constant volume. Pic then decreased approximately coincident with pseudopod formation. There was a positive correlation between Pic at the onset of movement and the rate of pseudopod formation. These results are the first direct evidence that hydrostatic pressure may be a motive force for cell motion. We postulate that contractile elements in the amoeba's cortical layer contract and increase Pic and that this Pic is utilized to overcome the viscous flow resistance of the intracellular contents during pseudopod formation. © 1996 Wiley‐Liss, Inc.

show abstract

Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Cited by 94 publications

References 32 publications

Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

Contractile basis of ameboid movement. VII. Aequorin luminescence during ameboid movement, endocytosis, and capping.

Intracellular pressure is a motive force for cell motion inAmoeba proteus

Contact Info

Product

Resources

About