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Specific SHP-2 partitioning in raft domains triggers integrin-mediated signaling via Rho activation.

Lacalle RA, Mira E, Gomez-Mouton C, Jimenez-Baranda S, Martinez-A C, Manes S - J. Cell Biol. (2002)

Bottom Line: Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts.By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling.Expression of the dominant negative N19Rho abrogates raft-SHP-2-induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, UAM Campus de Cantoblanco, E-28049 Madrid, Spain.

ABSTRACT
Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts. By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling. Serum-depleted, nonattached cells expressing the raft SHP-2 form, but not non-raft SHP-2, display signaling events resembling those observed after fibronectin attachment, such as beta1 integrin clustering, 397Y-FAK phosphorylation, and ERK activation, and also increases Rho-GTP levels. Expression of the dominant negative N19Rho abrogates raft-SHP-2-induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling. Expression of a catalytic inactive SHP-2 mutant abrogates the adhesion-induced feedback inhibition of Rho activity, suggesting that SHP-2 contributes to adhesion-induced suppression of Rho activity. Because raft recruitment of SHP-2 occurs physiologically after cell attachment, these results provide a mechanism by which SHP-2 may influence cell adhesion and migration by spatially regulating Rho activity.

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Related in: MedlinePlus

Cho depletion inhibits cell spreading. Serum-starved cells were untreated (−, ▴), CD-treated (•), or replenished with Cho after CD treatment (CD + Cho, ▪). Phase-contrast images were recorded at different times to evaluate cell spreading by direct counting. Representative fields and quantification are shown (n = 5).
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fig3: Cho depletion inhibits cell spreading. Serum-starved cells were untreated (−, ▴), CD-treated (•), or replenished with Cho after CD treatment (CD + Cho, ▪). Phase-contrast images were recorded at different times to evaluate cell spreading by direct counting. Representative fields and quantification are shown (n = 5).

Mentions: Identification of integrins and integrin-associated proteins in the DRM fraction indicates that early integrin signaling is engaged in rafts. In addition, depletion of membrane Cho with the drug methyl-β-cyclodextrin (CD) delays 293T cell spreading on Fn, which is restored by adding free Cho to CD-treated cells (Fig. 3); this suggests that cell spreading is dependent on levels of membrane Cho, a lipid particularly abundant in rafts.


Specific SHP-2 partitioning in raft domains triggers integrin-mediated signaling via Rho activation.

Lacalle RA, Mira E, Gomez-Mouton C, Jimenez-Baranda S, Martinez-A C, Manes S - J. Cell Biol. (2002)

Cho depletion inhibits cell spreading. Serum-starved cells were untreated (−, ▴), CD-treated (•), or replenished with Cho after CD treatment (CD + Cho, ▪). Phase-contrast images were recorded at different times to evaluate cell spreading by direct counting. Representative fields and quantification are shown (n = 5).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199243&req=5

fig3: Cho depletion inhibits cell spreading. Serum-starved cells were untreated (−, ▴), CD-treated (•), or replenished with Cho after CD treatment (CD + Cho, ▪). Phase-contrast images were recorded at different times to evaluate cell spreading by direct counting. Representative fields and quantification are shown (n = 5).
Mentions: Identification of integrins and integrin-associated proteins in the DRM fraction indicates that early integrin signaling is engaged in rafts. In addition, depletion of membrane Cho with the drug methyl-β-cyclodextrin (CD) delays 293T cell spreading on Fn, which is restored by adding free Cho to CD-treated cells (Fig. 3); this suggests that cell spreading is dependent on levels of membrane Cho, a lipid particularly abundant in rafts.

Bottom Line: Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts.By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling.Expression of the dominant negative N19Rho abrogates raft-SHP-2-induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, UAM Campus de Cantoblanco, E-28049 Madrid, Spain.

ABSTRACT
Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts. By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling. Serum-depleted, nonattached cells expressing the raft SHP-2 form, but not non-raft SHP-2, display signaling events resembling those observed after fibronectin attachment, such as beta1 integrin clustering, 397Y-FAK phosphorylation, and ERK activation, and also increases Rho-GTP levels. Expression of the dominant negative N19Rho abrogates raft-SHP-2-induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling. Expression of a catalytic inactive SHP-2 mutant abrogates the adhesion-induced feedback inhibition of Rho activity, suggesting that SHP-2 contributes to adhesion-induced suppression of Rho activity. Because raft recruitment of SHP-2 occurs physiologically after cell attachment, these results provide a mechanism by which SHP-2 may influence cell adhesion and migration by spatially regulating Rho activity.

Show MeSH
Related in: MedlinePlus