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The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting

The COOH-terminal polybasic region (PBR) of Rac1, a Rho family GTPase member, is required for Rac1 self-association, membrane localization, nuclear translocation, and interaction with downstream effectors. We previously demonstrated that phosphatidylinositol-4-phosphate 5-kinase, one of the effector...

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Autores principales: Wong, Ka-Wing, Mohammadi, Sina, Isberg, Ralph R.
Formato: Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2602895/
https://www.ncbi.nlm.nih.gov/pubmed/18940795
http://dx.doi.org/10.1074/jbc.M804717200
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author Wong, Ka-Wing
Mohammadi, Sina
Isberg, Ralph R.
author_facet Wong, Ka-Wing
Mohammadi, Sina
Isberg, Ralph R.
author_sort Wong, Ka-Wing
collection PubMed
description The COOH-terminal polybasic region (PBR) of Rac1, a Rho family GTPase member, is required for Rac1 self-association, membrane localization, nuclear translocation, and interaction with downstream effectors. We previously demonstrated that phosphatidylinositol-4-phosphate 5-kinase, one of the effectors that requires the polybasic region for interaction, is necessary for efficient invasin-promoted uptake of Yersinia pseudotuberculosis by nonphagocytic cells. Here we further examined the role of this region in invasin-promoted uptake. Using fluorescence resonance energy transfer experiments (FRET), we determined that engagement of integrin receptors by invasin caused elevated levels of Rac1 self-association at the site of bacterial adhesion in a PBR-dependent fashion. Self-association could be disrupted using several strategies: translocation of the Yersinia YopT prenylcysteine protease into host cells, inactivation of the Rac1 isoprenylation signal that is required for membrane localization, and elimination of the PBR. Disruption in each case impaired invasin-promoted uptake. To determine if there is a role for the PBR in Rac1 effector signaling that was independent of its role in membrane localization or multimerization, we examined the effect of the PBR in the context of a Rac1 derivative that was targeted to the membrane via an NH(2)-terminal lipid tail. The membrane-targeted Rac1 derivative restored significant invasin-promoted bacterial uptake in a PBR-dependent manner and yet displayed no detectable self-association. This study indicates that, in addition to its role in promoting membrane localization, the PBR exerts a positive effect on Rac1-controlled bacterial uptake that is independent of Rac1 self-association, most likely due to signaling to downstream effectors.
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spelling pubmed-26028952008-12-23 The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting Wong, Ka-Wing Mohammadi, Sina Isberg, Ralph R. J Biol Chem Mechanisms of Signal Transduction The COOH-terminal polybasic region (PBR) of Rac1, a Rho family GTPase member, is required for Rac1 self-association, membrane localization, nuclear translocation, and interaction with downstream effectors. We previously demonstrated that phosphatidylinositol-4-phosphate 5-kinase, one of the effectors that requires the polybasic region for interaction, is necessary for efficient invasin-promoted uptake of Yersinia pseudotuberculosis by nonphagocytic cells. Here we further examined the role of this region in invasin-promoted uptake. Using fluorescence resonance energy transfer experiments (FRET), we determined that engagement of integrin receptors by invasin caused elevated levels of Rac1 self-association at the site of bacterial adhesion in a PBR-dependent fashion. Self-association could be disrupted using several strategies: translocation of the Yersinia YopT prenylcysteine protease into host cells, inactivation of the Rac1 isoprenylation signal that is required for membrane localization, and elimination of the PBR. Disruption in each case impaired invasin-promoted uptake. To determine if there is a role for the PBR in Rac1 effector signaling that was independent of its role in membrane localization or multimerization, we examined the effect of the PBR in the context of a Rac1 derivative that was targeted to the membrane via an NH(2)-terminal lipid tail. The membrane-targeted Rac1 derivative restored significant invasin-promoted bacterial uptake in a PBR-dependent manner and yet displayed no detectable self-association. This study indicates that, in addition to its role in promoting membrane localization, the PBR exerts a positive effect on Rac1-controlled bacterial uptake that is independent of Rac1 self-association, most likely due to signaling to downstream effectors. American Society for Biochemistry and Molecular Biology 2008-12-19 /pmc/articles/PMC2602895/ /pubmed/18940795 http://dx.doi.org/10.1074/jbc.M804717200 Text en Copyright © 2008, The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) applies to Author Choice Articles
spellingShingle Mechanisms of Signal Transduction
Wong, Ka-Wing
Mohammadi, Sina
Isberg, Ralph R.
The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title_full The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title_fullStr The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title_full_unstemmed The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title_short The Polybasic Region of Rac1 Modulates Bacterial Uptake Independently of Self-association and Membrane Targeting
title_sort polybasic region of rac1 modulates bacterial uptake independently of self-association and membrane targeting
topic Mechanisms of Signal Transduction
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2602895/
https://www.ncbi.nlm.nih.gov/pubmed/18940795
http://dx.doi.org/10.1074/jbc.M804717200
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