Early changes in the distribution and organization of microfilament proteins during cell transformation

Boschek, C. B.; Jockusch, Brigitte M.; Friis, Robert R.; Back, Ruth; Grundmann, E.; Bauer, Heinz

doi:10.1016/0092-8674(81)90513-4

Cited by 186 publications

(78 citation statements)

References 34 publications

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“…It is noteworthy that some labeling of tyrosine phosphorylated proteins with the anti-phosphotyrosine antibody was apparent along the cell membrane and in actin-rich structures in non-transfected cells; however, the intensity of immunolabeling was signi®cantly lower than AFAP-110 Dlzip expressing cells. These structures appeared to represent lamellipodia, which are known to contain tyrosine phosphorylated proteins and whose formation and extension involve Src activation (Boschek et al, 1981;Schwartzberg et al, 1997). The levels of immunostaining for these tyrosine phosphorylated proteins was also noticeably lower in cells expressing wild-type AFAP-110, which was equivalent to untransfecteded cells (Figure 3a ± c).…”

Section: Afap-110 Dlzip Expression Activates Cellular Tyrosine Phosphmentioning

confidence: 85%

“…These changes include a repositioning of actin ®laments into rosettelike structures, and the formation of lamellipodia and ®lopodia, which are associated with increased cell motility and the onset of tumor metastasis in humans (Bolen et al, 1987;Boschek et al, 1981;Cartwright et al, 1990;Irby et al, 1999;Rosen et al, 1986;Tarone et al, 1985). The cSrc proto-oncogene can be activated by dephosphorylation of Tyr 527 by cellular phosphatases, or displacement of repressive, intramolecular interactions involving the SH2 and SH3 domains (Brown and Cooper, 1996).…”

Section: Introductionmentioning

confidence: 99%

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The intrinsic ability of AFAP-110 to alter actin filament integrity is linked with its ability to also activate cellular tyrosine kinases

et al. 2001

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The actin ®lament-associated protein of 110 kDa (AFAP-110) is a Src binding partner that represents a potential modulator of actin ®lament integrity in response to cellular signals. Previous reports have demonstrated that AFAP-110 is capable of directly binding and altering actin ®laments. Deletion of the leucine zipper motif of AFAP-110 (AFAP-110 Dlzip ) has been shown to induce a phenotype which resembles Srctransformed cells, by repositioning actin ®laments into rosettes. This deletion also mimics a conformational change in AFAP-110 that is detected in Src-transformed cells. The results presented here indicate that unlike AFAP-110, AFAP-110 Dlzip is capable of activating cellular tyrosine kinases, including Src family members, and that AFAP-110 Dlzip itself is hyperphosphorylated. The newly tyrosine phosphorylated proteins and activated Src-family members appear to be associated with actinrich lamellipodia. A point mutation that alters the SH3-binding motif of AFAP-110 Dlzip prevents it from activating tyrosine kinases and altering actin ®lament integrity. In addition, a deletion within a pleckstrin homology (PH) domain of AFAP-110 Dlzip will also revert its e ects upon actin ®laments. Lastly, dominant-positive RhoA V14 will block the ability of AFAP-110 Dlzip from inducing actin ®lament rosettes, but does not inhibit Src activation. Thus, conformational changes in AFAP-110 enable it to activate cellular kinases in a mechanism requiring SH3 and/or PH domain interactions. We hypothesize that cellular signals which alter AFAP-110 conformation, enable it to activate cellular kinases such as cSrc, which then direct changes in actin ®lament integrity in a Rho-dependent fashion. Oncogene (2001) 20, 6607 ± 6616.

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Section: Afap-110 Dlzip Expression Activates Cellular Tyrosine Phosphmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

The intrinsic ability of AFAP-110 to alter actin filament integrity is linked with its ability to also activate cellular tyrosine kinases

et al. 2001

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“…Loss of the filamentous actin is one of the earliest morphological changes in pp60 ...... transformed cells (5,57). As the depolymerization of actin was prevented by DFMO treatment, it is tempting to speculate that polyamines might play a role in the organization of the actin filaments through their effect on the phosphorylation of calpactins and other proteins associating with, or being integral components of the cytoskeleton.…”

Section: Cytoskeletal Rearrangements May Be Regulated By Polyamine-dementioning

confidence: 99%

Polyamines are essential for cell transformation by pp60v-src: delineation of molecular events relevant for the transformed phenotype

Hölttä

Auvinen

Andersson

1993

The Journal of Cell Biology

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Abstract. Ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis, becomes upregulated during cell proliferation and transformation. Here we show that intact ODC activity is needed for the acquisition of a transformed phenotype in rat 2R cells infected with a temperature-sensitive mutant of Rous sarcoma virus. Addition of the ODC inhibitor tx-difluoromethyl ornithine (DFMO) to the cells (in polyamine-free medium) before shift to permissive temperature prevented the depolymerization of filamentous actin and morphological transformation. Polyamine supplementation restored the transforming potential of pp60 ~-'r~. DFMO did not interfere with the expression of pp60 v-'r~ or its in vitro tyrosine kinase activity. The tyrosine phosphorylation of most cellular proteins, including ras GAP, did not either display clear temperature-or DFMO-sensitive changes. A marked increase was, however, observed in the tyrosine phosphorylation of phosphatidylinositol 3-kinase and proteins of 33 and 36 kD upon the temperature shift, and these hyperphosphorylations were partially inhibited by DFMO. A DFMO-sensitive increase was also found in the total phosphorylation of calpactins I and II. The well-documented association of GAP with the phosphotyrosine-containing proteins p190 and p62 did not correlate with transformation, but a novel 42-kD tyrosine phosphorylated protein was complexed with GAP in a polyamine-and transformationdependent manner. Further, tyrosine phosphorylated proteins of 130, 80/85, and 36 kD were found to coimmunoprecipitate with pp60 v-s~ in a transformationrelated manner. Altogether, this model offers a tool for sorting out the protein phosphorylations and associations critical for the transformed phenotype triggered by pp60 v-'~, and implicates a pivotal role for polyo amines in cell transformation. RNITHINE decarboxylase (ODC), 1 which catalyzes the formation of putrescine and CO2 from ornithine, is the rate-controlling enzyme in the biosynthesis of polyamines. ODC and polyamines have been implicated to play a pivotal role in cell proliferation and to contribute to the development of cancer (28,48,61). Mitogenic stimulation of normal cells triggers a rapid, transient increase in ODC activity, whereas cell transformation by chemical carcinogens (22), viruses (21, 25, 35) and oncogenes (34,59, 60) appears to be accompanied by a constitutive activation of ODC and loss of the cell cycle-related fluctuations in the enzyme activity. To assess the significance of the ODC induction for the transformation process, we decided to examine the effects of ot-difluoromethyl ornithine (DFMO), a highly specific and irreversible inhibitor of ODC (44), on different parameters of transformation in a rat fibroblast ceil line (2R) having a temperature-sensitive Rous sarcoma virus (RSV) mutant integrated into the genome (63).The transforming gene of RSV, v-src, encodes a 60-kD

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“…Immunofluoroscence microscopy has demonstrated larger microfilament bundle networks within whole cells (Goldman et al, 1975) and a reduction in the number and thickness of the bundles has been demonstrated following viral transformation by RNA viruses (Ash et al, 1976, Wang & Goldberg, 1979, Boschek et al, 1981 and DNA viruses . However, the limited resolution of this technique does not identify the finer detail of these changes.…”

Section: Discussionmentioning

confidence: 99%

“…One of the cellular targets for this pp6O kinase activity may be some component of the cytoskeleton (Burr et al, 1980;, since many RSV-transformed cells show a reduction in actin-containing microfilament bundles and a reduction in vinculin-containing adhesion plaques, with a redistribution of these proteins towards membrane-associated complexes. These changes seem to be dependent upon the presence of a continually active src gene and they occur at an early stage in the transformation process (Maness et al, 1979;Boschek et al, 1981).…”

mentioning

confidence: 99%

Effect of transformation by Rous sarcoma virus on the character and distribution of actin in Rat-1 fibroblasts: A biochemical and microscopical study

Holme¹,

Kellie²,

Wyke³

et al. 1986

Br J Cancer

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Actin has been measured in subcellular fractions from Rat-1 fibroblasts and in Rous sarcoma virus-transformed Rat-1 cells (VIT), using the DNase 1 inhibition assay. The transformed cells showed a significant shift in the actin monomer (G)in equilibrium with polymer (F) equilibrium within the cell cytosol, and a significant increase in actin in the Triton-insoluble cytoskeletal core in comparison with untransformed cells. This incorporation of actin into the cytoskeletal core fraction is associated with a change in filamentous actin assemblies from 'stress fibre' patterns to punctate filament aggregates. These differences have been correlated with changes in morphology, in actin, vinculin and alpha-actinin distribution, in adhesion plaque formation and with the production of pp60v-src-associated protein kinase activity in the transformed cells. Changes in actin distribution and its polymerization in response to src-gene expression may play an important role in the determination of the transformed cell characteristics. Images Figure 1 Figure 2 p471-a Figure 3 Figure 4 Figure 5

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Early changes in the distribution and organization of microfilament proteins during cell transformation

Cited by 186 publications

References 34 publications

The intrinsic ability of AFAP-110 to alter actin filament integrity is linked with its ability to also activate cellular tyrosine kinases

The intrinsic ability of AFAP-110 to alter actin filament integrity is linked with its ability to also activate cellular tyrosine kinases

Polyamines are essential for cell transformation by pp60v-src: delineation of molecular events relevant for the transformed phenotype

Effect of transformation by Rous sarcoma virus on the character and distribution of actin in Rat-1 fibroblasts: A biochemical and microscopical study

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