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Role of the PI3K regulatory subunit in the control of actin organization and cell migration.

Jiménez C, Portela RA, Mellado M, Rodríguez-Frade JM, Collard J, Serrano A, Martínez-A C, Avila J, Carrera AC - J. Cell Biol. (2000)

Bottom Line: We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes.Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K.Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología, Madrid, Spain.

ABSTRACT
Cell migration represents an important cellular response that utilizes cytoskeletal reorganization as its driving force. Here, we describe a new signaling cascade linking PDGF receptor stimulation to actin rearrangements and cell migration. We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes. Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K. Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen. These observations show the essential role of the PI3K regulatory subunit p85alpha in controlling PDGF receptor-induced cytoskeletal changes and cell migration, illustrating a novel signaling pathway that links receptor stimulation at the cell membrane with actin dynamics.

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Related in: MedlinePlus

PDGF receptor stimulation induces actin stress fiber disassembly and a decrease in focal adhesion complexes. NIH-3T3 cells were incubated for 16 h in 0.1% serum. After starvation, cells were incubated for 10 min with medium, or with PDGF (50 ng/ml), or with LPA (10 ng/ml), or with a combination of LPA (10 ng/ml) and PDGF (50 ng/ml). Cells were stimulated, fixed, and stained for filamentous actin using FITC-conjugated phalloidin and for paxillin distribution by indirect immunofluorescence. Images were collected by confocal microscopy. Paxillin images in PDGF-treated samples were overexposed to detect the low intensity peripheral focal adhesion complexes. The figure illustrates one representative experiment of five performed with similar results. Bar, 100 μm.
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Figure 1: PDGF receptor stimulation induces actin stress fiber disassembly and a decrease in focal adhesion complexes. NIH-3T3 cells were incubated for 16 h in 0.1% serum. After starvation, cells were incubated for 10 min with medium, or with PDGF (50 ng/ml), or with LPA (10 ng/ml), or with a combination of LPA (10 ng/ml) and PDGF (50 ng/ml). Cells were stimulated, fixed, and stained for filamentous actin using FITC-conjugated phalloidin and for paxillin distribution by indirect immunofluorescence. Images were collected by confocal microscopy. Paxillin images in PDGF-treated samples were overexposed to detect the low intensity peripheral focal adhesion complexes. The figure illustrates one representative experiment of five performed with similar results. Bar, 100 μm.

Mentions: Here, we examine the mechanisms mediating PDGF-induced cytoskeletal changes in NIH-3T3 cells. PDGF treatment not only induces membrane ruffling and lamellipodial extensions, but also a decrease in LPA-stimulated actin stress fibers and focal adhesions (Fig. 1; Bockus and Stiles 1984; Ridley and Hall 1994; Wennström et al. 1994b).


Role of the PI3K regulatory subunit in the control of actin organization and cell migration.

Jiménez C, Portela RA, Mellado M, Rodríguez-Frade JM, Collard J, Serrano A, Martínez-A C, Avila J, Carrera AC - J. Cell Biol. (2000)

PDGF receptor stimulation induces actin stress fiber disassembly and a decrease in focal adhesion complexes. NIH-3T3 cells were incubated for 16 h in 0.1% serum. After starvation, cells were incubated for 10 min with medium, or with PDGF (50 ng/ml), or with LPA (10 ng/ml), or with a combination of LPA (10 ng/ml) and PDGF (50 ng/ml). Cells were stimulated, fixed, and stained for filamentous actin using FITC-conjugated phalloidin and for paxillin distribution by indirect immunofluorescence. Images were collected by confocal microscopy. Paxillin images in PDGF-treated samples were overexposed to detect the low intensity peripheral focal adhesion complexes. The figure illustrates one representative experiment of five performed with similar results. Bar, 100 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2192656&req=5

Figure 1: PDGF receptor stimulation induces actin stress fiber disassembly and a decrease in focal adhesion complexes. NIH-3T3 cells were incubated for 16 h in 0.1% serum. After starvation, cells were incubated for 10 min with medium, or with PDGF (50 ng/ml), or with LPA (10 ng/ml), or with a combination of LPA (10 ng/ml) and PDGF (50 ng/ml). Cells were stimulated, fixed, and stained for filamentous actin using FITC-conjugated phalloidin and for paxillin distribution by indirect immunofluorescence. Images were collected by confocal microscopy. Paxillin images in PDGF-treated samples were overexposed to detect the low intensity peripheral focal adhesion complexes. The figure illustrates one representative experiment of five performed with similar results. Bar, 100 μm.
Mentions: Here, we examine the mechanisms mediating PDGF-induced cytoskeletal changes in NIH-3T3 cells. PDGF treatment not only induces membrane ruffling and lamellipodial extensions, but also a decrease in LPA-stimulated actin stress fibers and focal adhesions (Fig. 1; Bockus and Stiles 1984; Ridley and Hall 1994; Wennström et al. 1994b).

Bottom Line: We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes.Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K.Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología, Madrid, Spain.

ABSTRACT
Cell migration represents an important cellular response that utilizes cytoskeletal reorganization as its driving force. Here, we describe a new signaling cascade linking PDGF receptor stimulation to actin rearrangements and cell migration. We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes. Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K. Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen. These observations show the essential role of the PI3K regulatory subunit p85alpha in controlling PDGF receptor-induced cytoskeletal changes and cell migration, illustrating a novel signaling pathway that links receptor stimulation at the cell membrane with actin dynamics.

Show MeSH
Related in: MedlinePlus