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Focal adhesions are foci for tyrosine-based signal transduction via GIV/Girdin and G proteins.

Lopez-Sanchez I, Kalogriopoulos N, Lo IC, Kabir F, Midde KK, Wang H, Ghosh P - Mol. Biol. Cell (2015)

Bottom Line: As a guanidine exchange factor (GEF), GIV modulates signals initiated by growth factors (chemical signals) by activating the G protein Gαi.Activation of Gαi by GIV-GEF further potentiates FAK-GIV-PI3K-Akt signaling at the FAs.Spatially restricted signaling via tyrosine phosphorylated GIV at the FAs is enhanced during cancer metastasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093 inmalopezsanchez@hotmail.com prghosh@ucsd.edu.

No MeSH data available.


Related in: MedlinePlus

GIV colocalizes with bundles of β1 integrins and couples G proteins to β1 integrins. (A, B) HeLa cells grown on a poly-d-lysine–coated surface were resuspended, plated on collagen-coated surface for ∼10 min, fixed, stained for β1 integrin (green), DAPI (nuclei; blue), and either GIV (red; A) or pYGIV (red; B) and analyzed by confocal microscopy. A line scan plot of relative fluorescence intensities of β1 integrin and GIV in A was analyzed using the RGB profiler plug-in from Image J. Bar, 25 μm. (C) HeLa cells grown on poly-d-lysine were stimulated (+) or not (–) with collagen and lysed, and the lysates were subjected to immunoprecipitation using anti–β1 integrin antibody. Immune complexes were analyzed for GIV, β1 integrin, and Gα3 by immunoblotting. (D) Schematic illustration summarizing how GIV-GEF modulates tyrosine-based and G protein signaling in the vicinity of ligand-activated β1 integrins.
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Figure 4: GIV colocalizes with bundles of β1 integrins and couples G proteins to β1 integrins. (A, B) HeLa cells grown on a poly-d-lysine–coated surface were resuspended, plated on collagen-coated surface for ∼10 min, fixed, stained for β1 integrin (green), DAPI (nuclei; blue), and either GIV (red; A) or pYGIV (red; B) and analyzed by confocal microscopy. A line scan plot of relative fluorescence intensities of β1 integrin and GIV in A was analyzed using the RGB profiler plug-in from Image J. Bar, 25 μm. (C) HeLa cells grown on poly-d-lysine were stimulated (+) or not (–) with collagen and lysed, and the lysates were subjected to immunoprecipitation using anti–β1 integrin antibody. Immune complexes were analyzed for GIV, β1 integrin, and Gα3 by immunoblotting. (D) Schematic illustration summarizing how GIV-GEF modulates tyrosine-based and G protein signaling in the vicinity of ligand-activated β1 integrins.

Mentions: Next we asked whether active GIV colocalizes with integrins and specifically examined β1 integrins, a major subunit of collagen I–binding integrins (Jokinen et al., 2004). Immunofluorescence studies confirmed that both total (Figure 4A) and active pYGIV (Figure 4B) colocalized with integrin clusters, as well as with bundles of β1 integrin, within 10 min after acute stimulation with collagen and continued to show more prominent colocalization at 30 min and 2 h (unpublished data).


Focal adhesions are foci for tyrosine-based signal transduction via GIV/Girdin and G proteins.

Lopez-Sanchez I, Kalogriopoulos N, Lo IC, Kabir F, Midde KK, Wang H, Ghosh P - Mol. Biol. Cell (2015)

GIV colocalizes with bundles of β1 integrins and couples G proteins to β1 integrins. (A, B) HeLa cells grown on a poly-d-lysine–coated surface were resuspended, plated on collagen-coated surface for ∼10 min, fixed, stained for β1 integrin (green), DAPI (nuclei; blue), and either GIV (red; A) or pYGIV (red; B) and analyzed by confocal microscopy. A line scan plot of relative fluorescence intensities of β1 integrin and GIV in A was analyzed using the RGB profiler plug-in from Image J. Bar, 25 μm. (C) HeLa cells grown on poly-d-lysine were stimulated (+) or not (–) with collagen and lysed, and the lysates were subjected to immunoprecipitation using anti–β1 integrin antibody. Immune complexes were analyzed for GIV, β1 integrin, and Gα3 by immunoblotting. (D) Schematic illustration summarizing how GIV-GEF modulates tyrosine-based and G protein signaling in the vicinity of ligand-activated β1 integrins.
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Related In: Results  -  Collection

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Figure 4: GIV colocalizes with bundles of β1 integrins and couples G proteins to β1 integrins. (A, B) HeLa cells grown on a poly-d-lysine–coated surface were resuspended, plated on collagen-coated surface for ∼10 min, fixed, stained for β1 integrin (green), DAPI (nuclei; blue), and either GIV (red; A) or pYGIV (red; B) and analyzed by confocal microscopy. A line scan plot of relative fluorescence intensities of β1 integrin and GIV in A was analyzed using the RGB profiler plug-in from Image J. Bar, 25 μm. (C) HeLa cells grown on poly-d-lysine were stimulated (+) or not (–) with collagen and lysed, and the lysates were subjected to immunoprecipitation using anti–β1 integrin antibody. Immune complexes were analyzed for GIV, β1 integrin, and Gα3 by immunoblotting. (D) Schematic illustration summarizing how GIV-GEF modulates tyrosine-based and G protein signaling in the vicinity of ligand-activated β1 integrins.
Mentions: Next we asked whether active GIV colocalizes with integrins and specifically examined β1 integrins, a major subunit of collagen I–binding integrins (Jokinen et al., 2004). Immunofluorescence studies confirmed that both total (Figure 4A) and active pYGIV (Figure 4B) colocalized with integrin clusters, as well as with bundles of β1 integrin, within 10 min after acute stimulation with collagen and continued to show more prominent colocalization at 30 min and 2 h (unpublished data).

Bottom Line: As a guanidine exchange factor (GEF), GIV modulates signals initiated by growth factors (chemical signals) by activating the G protein Gαi.Activation of Gαi by GIV-GEF further potentiates FAK-GIV-PI3K-Akt signaling at the FAs.Spatially restricted signaling via tyrosine phosphorylated GIV at the FAs is enhanced during cancer metastasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093 inmalopezsanchez@hotmail.com prghosh@ucsd.edu.

No MeSH data available.


Related in: MedlinePlus