βPak-interacting exchange factor-mediated Rac1 activation requires smgGDS guanine nucleotide exchange factor in basic fibroblast growth factor-induced neurite outgrowth

Eun Young Shin, Chan Soo Lee, Goo Cho Tae, Gyu Kim Young, Sukgil Song, Yong-Sung Juhnn, Chul Park Sang, Ed Manser, Eung Gook Kim

Research output: Contribution to journalArticleResearchpeer-review

17 Citations (Scopus)

Abstract

Neuritogenesis requires active actin cytoskeleton rearrangement in which Rho GTPases play a pivotal role. In a previous study (Shin, E. Y., Woo, K. N., Lee, C. S., Koo, S. H., Kim, Y. G., Kim, W. J., Bae, C. D., Chang, S. I., and Kim, E. G. (2004) J. Biol. Chem. 279, 1994-2004), we demonstrated that βPak-interacting exchange factor (βPIX) guanine nucleotide exchange factor (GEF) mediates basic fibroblast growth factor (bFGF)-stimulated Rac1 activation through phosphorylation of Ser-525 and Thr-526 at the GIT-binding domain (GBD). However, the mechanism by which this phosphorylation event regulates the Rac1-GEF activity remained elusive.Weshow here that βPIX binds to Rac1 via the GBD and also activates the GTPase via an associated GEF, smgGDS, in a phosphorylation-dependent manner. Notably, the Rac1-GEF activity of βPIX persisted for an extended period of time following bFGF stimulation, unlike other Rho GEFs containing the Dbl homology domain. We demonstrate that C-PIX, containing proline-rich, GBD, and leucine zipper domains can interact with Rac1 via the GBD in vitro and in vivo and also mediated bFGF-stimulated Rac1 activation, as determined by a modified GEF assay and fluorescence resonance energy transfer analysis. However, nonphosphorylatable C-PIX (S525A/T526A) failed to generate Rac1-GTP. Finally, βPIX is shown to form a trimeric complex with smgGDS and Rac1; down-regulation of smgGDS expression by short interfering RNA causing significant inhibition of βPIX-mediated Rac1 activation and neurite outgrowth. These results provide evidence for a new and unexpected mechanism whereby βPIX can regulate Rac1 activity.

Original languageEnglish
Pages (from-to)35954-35964
Number of pages11
JournalJournal of Biological Chemistry
Volume281
Issue number47
DOIs
StatePublished - 24 Nov 2006

Fingerprint

Guanine Nucleotide Exchange Factors
Fibroblast Growth Factor 2
Ion exchange
Chemical activation
Phosphorylation
Leucine Zippers
rho GTP-Binding Proteins
Fluorescence Resonance Energy Transfer
GTP Phosphohydrolases
Guanosine Triphosphate
Actin Cytoskeleton
Proline
Small Interfering RNA
Actins
Assays
Down-Regulation
Neuronal Outgrowth

Cite this

Shin, Eun Young ; Lee, Chan Soo ; Tae, Goo Cho ; Young, Gyu Kim ; Song, Sukgil ; Juhnn, Yong-Sung ; Sang, Chul Park ; Manser, Ed ; Kim, Eung Gook. / βPak-interacting exchange factor-mediated Rac1 activation requires smgGDS guanine nucleotide exchange factor in basic fibroblast growth factor-induced neurite outgrowth. In: Journal of Biological Chemistry. 2006 ; Vol. 281, No. 47. pp. 35954-35964.
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title = "βPak-interacting exchange factor-mediated Rac1 activation requires smgGDS guanine nucleotide exchange factor in basic fibroblast growth factor-induced neurite outgrowth",
abstract = "Neuritogenesis requires active actin cytoskeleton rearrangement in which Rho GTPases play a pivotal role. In a previous study (Shin, E. Y., Woo, K. N., Lee, C. S., Koo, S. H., Kim, Y. G., Kim, W. J., Bae, C. D., Chang, S. I., and Kim, E. G. (2004) J. Biol. Chem. 279, 1994-2004), we demonstrated that βPak-interacting exchange factor (βPIX) guanine nucleotide exchange factor (GEF) mediates basic fibroblast growth factor (bFGF)-stimulated Rac1 activation through phosphorylation of Ser-525 and Thr-526 at the GIT-binding domain (GBD). However, the mechanism by which this phosphorylation event regulates the Rac1-GEF activity remained elusive.Weshow here that βPIX binds to Rac1 via the GBD and also activates the GTPase via an associated GEF, smgGDS, in a phosphorylation-dependent manner. Notably, the Rac1-GEF activity of βPIX persisted for an extended period of time following bFGF stimulation, unlike other Rho GEFs containing the Dbl homology domain. We demonstrate that C-PIX, containing proline-rich, GBD, and leucine zipper domains can interact with Rac1 via the GBD in vitro and in vivo and also mediated bFGF-stimulated Rac1 activation, as determined by a modified GEF assay and fluorescence resonance energy transfer analysis. However, nonphosphorylatable C-PIX (S525A/T526A) failed to generate Rac1-GTP. Finally, βPIX is shown to form a trimeric complex with smgGDS and Rac1; down-regulation of smgGDS expression by short interfering RNA causing significant inhibition of βPIX-mediated Rac1 activation and neurite outgrowth. These results provide evidence for a new and unexpected mechanism whereby βPIX can regulate Rac1 activity.",
author = "Shin, {Eun Young} and Lee, {Chan Soo} and Tae, {Goo Cho} and Young, {Gyu Kim} and Sukgil Song and Yong-Sung Juhnn and Sang, {Chul Park} and Ed Manser and Kim, {Eung Gook}",
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βPak-interacting exchange factor-mediated Rac1 activation requires smgGDS guanine nucleotide exchange factor in basic fibroblast growth factor-induced neurite outgrowth. / Shin, Eun Young; Lee, Chan Soo; Tae, Goo Cho; Young, Gyu Kim; Song, Sukgil; Juhnn, Yong-Sung; Sang, Chul Park; Manser, Ed; Kim, Eung Gook.

In: Journal of Biological Chemistry, Vol. 281, No. 47, 24.11.2006, p. 35954-35964.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - βPak-interacting exchange factor-mediated Rac1 activation requires smgGDS guanine nucleotide exchange factor in basic fibroblast growth factor-induced neurite outgrowth

AU - Shin, Eun Young

AU - Lee, Chan Soo

AU - Tae, Goo Cho

AU - Young, Gyu Kim

AU - Song, Sukgil

AU - Juhnn, Yong-Sung

AU - Sang, Chul Park

AU - Manser, Ed

AU - Kim, Eung Gook

PY - 2006/11/24

Y1 - 2006/11/24

N2 - Neuritogenesis requires active actin cytoskeleton rearrangement in which Rho GTPases play a pivotal role. In a previous study (Shin, E. Y., Woo, K. N., Lee, C. S., Koo, S. H., Kim, Y. G., Kim, W. J., Bae, C. D., Chang, S. I., and Kim, E. G. (2004) J. Biol. Chem. 279, 1994-2004), we demonstrated that βPak-interacting exchange factor (βPIX) guanine nucleotide exchange factor (GEF) mediates basic fibroblast growth factor (bFGF)-stimulated Rac1 activation through phosphorylation of Ser-525 and Thr-526 at the GIT-binding domain (GBD). However, the mechanism by which this phosphorylation event regulates the Rac1-GEF activity remained elusive.Weshow here that βPIX binds to Rac1 via the GBD and also activates the GTPase via an associated GEF, smgGDS, in a phosphorylation-dependent manner. Notably, the Rac1-GEF activity of βPIX persisted for an extended period of time following bFGF stimulation, unlike other Rho GEFs containing the Dbl homology domain. We demonstrate that C-PIX, containing proline-rich, GBD, and leucine zipper domains can interact with Rac1 via the GBD in vitro and in vivo and also mediated bFGF-stimulated Rac1 activation, as determined by a modified GEF assay and fluorescence resonance energy transfer analysis. However, nonphosphorylatable C-PIX (S525A/T526A) failed to generate Rac1-GTP. Finally, βPIX is shown to form a trimeric complex with smgGDS and Rac1; down-regulation of smgGDS expression by short interfering RNA causing significant inhibition of βPIX-mediated Rac1 activation and neurite outgrowth. These results provide evidence for a new and unexpected mechanism whereby βPIX can regulate Rac1 activity.

AB - Neuritogenesis requires active actin cytoskeleton rearrangement in which Rho GTPases play a pivotal role. In a previous study (Shin, E. Y., Woo, K. N., Lee, C. S., Koo, S. H., Kim, Y. G., Kim, W. J., Bae, C. D., Chang, S. I., and Kim, E. G. (2004) J. Biol. Chem. 279, 1994-2004), we demonstrated that βPak-interacting exchange factor (βPIX) guanine nucleotide exchange factor (GEF) mediates basic fibroblast growth factor (bFGF)-stimulated Rac1 activation through phosphorylation of Ser-525 and Thr-526 at the GIT-binding domain (GBD). However, the mechanism by which this phosphorylation event regulates the Rac1-GEF activity remained elusive.Weshow here that βPIX binds to Rac1 via the GBD and also activates the GTPase via an associated GEF, smgGDS, in a phosphorylation-dependent manner. Notably, the Rac1-GEF activity of βPIX persisted for an extended period of time following bFGF stimulation, unlike other Rho GEFs containing the Dbl homology domain. We demonstrate that C-PIX, containing proline-rich, GBD, and leucine zipper domains can interact with Rac1 via the GBD in vitro and in vivo and also mediated bFGF-stimulated Rac1 activation, as determined by a modified GEF assay and fluorescence resonance energy transfer analysis. However, nonphosphorylatable C-PIX (S525A/T526A) failed to generate Rac1-GTP. Finally, βPIX is shown to form a trimeric complex with smgGDS and Rac1; down-regulation of smgGDS expression by short interfering RNA causing significant inhibition of βPIX-mediated Rac1 activation and neurite outgrowth. These results provide evidence for a new and unexpected mechanism whereby βPIX can regulate Rac1 activity.

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U2 - 10.1074/jbc.M602399200

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M3 - Article

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