Microtubule-disrupting agents affect two different events regulating the initiation of DNA synthesis in Swiss 3T3 cells.

Otto, Angela M.; Ulrich, M O; Zumbe, Albert; Asúa, Luis Jiménez de

doi:10.1073/pnas.78.5.3063

Cited by 37 publications

(15 citation statements)

References 19 publications

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“…We know that microtubule depolymerization can initiate DNA synthesis in quiescent fibroblasts in the absence of added growth factors (12,28). Furthermore, a number of studies have now shown that the mitogenic effect of growth factors including EGF is substantially augmented by antimicrotubule drugs (18,25,30,31,41) . Thus, there is reason to suspect that microtubule reorganization is necessary for initiation of DNA synthesis by EGF and other growth factors .…”

Section: Discussionmentioning

confidence: 99%

Epidermal growth factor induces rapid centrosomal separation in HeLa and 3T3 cells.

Sherline¹,

Mascardo²

1982

The Journal of Cell Biology

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Using indirect immunofluorescence, we have found that epidermal growth factor (EGF), at 100 ng/ml, induces centrosomal separation within 20 min in HeLa and 3T3 cells. The effect was evident both in unsynchronized cultures and in HeLa cells blocked in early S phase by hydroxyurea. EGF also induced centrosomal separation in quiescent 3T3 cells blocked in Go/G 1 by serum deprivation, indicating that DNA replication is not necessary for this effect . The mechanism of this rapid centrosomal separation and its role in the mitogenic effects of EGF remains to be determined .Epidermal growth factor (EGF) (6,045 mol wt) is probably the most extensively studied mammalian mitogenic peptide (6) . EGF was originally isolated from mouse submaxillary glands but it is clearly made by other tissues because submaxillary gland excision does not lower plasma levels of EGF (4) . In man, EGF is found in plasma, saliva, and urine but its precise physiological role is unknown (13, 37). Since a wide variety of cells of epithelial (19,33,39), fibroblastic (1, 2, 5, 21), and neuronal (45) origin are stimulated to proliferate in vitro in response to EGF, it seems that this peptide is likely to be an important regulator of cell division in vivo.As with all other peptide hormones studied thus far, the initial event in the action of EGF is binding to specific highaffinity receptors on the external surface of the plasma membrane (1, 5, 6, 21); 15-22 h later DNA synthesis ensues with subsequent cell replication (1,5,6,22) . Although it is clear that major changes in the organization and function ofthe cell must occur in response to EGF before cell division, the key events leading from membrane binding to cell division are unknown.Centrosomes are perinuclear structures which consist of a pair of centrioles surrounded by an electron-dense cloud of pericentriolar material (34,40). During interphase many cytoplasmic microtubules originate from this structure (14,17,29). During mitosis a centrosome is located at each spindle pole and serves as an anchoring site for microtubules that make up the spindle apparatus . The centriole cycle, which includes duplication, elongation, and polar migration is, in general, believed to be tightly coupled to the cell cycle but the precise relationship between centriole and cell-cycle events remains to be elucidated. For example, while centriole formation can proceed in the absence of DNA synthesis (26, 32) it does require the presence of the nucleus (26). Whether centrosomal behavior influences nuclear events is an open question.Using a specific antiserum to a high molecular weight microtubule-associated protein (MAP,), which stains centrosomes THE JOURNAL OF CELL BIOLOGY " VOLUME 93 MAY 1982 507-511 © The Rockefeller University Press " 0021-9525/82/05/0507/06 $1 .00 in a variety ofcells, we have found that, after addition of EGF, the centrosome splits . The paired daughter centrosomes maintain close contact with the nucleus but migrate away from one another along the nuclear surface . The rapidity ofthe re...

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Section: Discussionmentioning

confidence: 99%

Epidermal growth factor induces rapid centrosomal separation in HeLa and 3T3 cells.

Sherline¹,

Mascardo²

1982

The Journal of Cell Biology

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“…Furthermore, it is weil known that microtubules cannot bend sharply (e.g., Crossin and Carney, 1981). Thus, and indentation of 0.5 f.Lm could prevent continued microtubule polymerization, and directly signal for cell differentiation because a population of microtubules would not be able to continue to elongate (Otto et al, 1981;Hoch et a/., 1987c). It is quite conceivable that microtubules may have only a secondary role in signal reception (viz., only be involved in mediation of the signal to the nucleus and/or in architectural changes of the germ tube tip resulting in appressorium formation).…”

Section: Thigmotropic Receptorsmentioning

confidence: 95%

Signaling for Infection Structure Formation in Fungi

Hoch

Staples

1991

The Fungal Spore and Disease Initiation in Plants and Animals

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“…For example, we have previously shown that microtubule stabilization by taxol inhibits initiation of DNA synthesis by a-thrombin or EGF, even when taxol is added up to 8 hr after the growth factors [ 191. Microtubule disruption enhances initiation of DNA synthesis by EGF [36] and by agents which increase intracellular CAMP [37]. Thus, enzymically active y-thrombin might initiate ion fluxes and cytoskeletal changes whereas receptor occupancy by DIP-a-thrombin activates a completely different set of metabolic effects.…”

Section: Mrcr:65mentioning

confidence: 96%

Initiation of proliferative events by human α‐thrombin requires both receptor binding and enzymic activity

Carney

Stiernberg

Fenton

1984

J of Cellular Biochemistry

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To determine the role of thrombin high-affinity receptor occupancy and enzymic activity in thrombin initiation of cell proliferation, we have utilized thrombin derivatives which separate these functions. We previously showed that enzymically active gamma-thrombin stimulates ion fluxes without binding to high-affinity sites, whereas proteolytically inhibited DIP-alpha-thrombin which binds to high-affinity receptors does not. Since neither derivative initiates DNA synthesis by itself, this suggested that two separate sequences of events might be necessary for a complete initiation signal. We now report that the combination of DIP-alpha-thrombin and gamma-thrombin initiate DNA synthesis and cell proliferation to levels approaching the maximal initiation by native alpha-thrombin. This combinatory effect is dose-dependent for both gamma-thrombin and DIP-alpha-thrombin in the same concentration range as alpha-thrombin alone. Thus, these same concentrations of alpha-thrombin alone may be required to initiate each sequence of events. The combinatory stimulation could be achieved even if the derivatives were added individually up to 8 hr apart. Moreover, preincubation with either derivative shortened the lag period for initiation of DNA synthesis by native alpha-thrombin. These results indicate that both receptor occupancy and enzymic activity are necessary for thrombin initiation of cell proliferation and that each action initiates a sequence of early events which moves the cell forward toward entry into a proliferative cycle.

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Microtubule-disrupting agents affect two different events regulating the initiation of DNA synthesis in Swiss 3T3 cells.

Cited by 37 publications

References 19 publications

Epidermal growth factor induces rapid centrosomal separation in HeLa and 3T3 cells.

Epidermal growth factor induces rapid centrosomal separation in HeLa and 3T3 cells.

Signaling for Infection Structure Formation in Fungi

Initiation of proliferative events by human α‐thrombin requires both receptor binding and enzymic activity

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