Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin
Chimaerins are a family of GTPase activating proteins (GAPs) for the small G-protein Rac that have gained recent attention due to their important roles in development, cancer, neuritogenesis, and T-cell function. Like protein kinase C isozymes, chimaerins possess a C1 domain capable of binding phorb...
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2008
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Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v283_n50_p35247_ColonGonzalez http://hdl.handle.net/20.500.12110/paper_00219258_v283_n50_p35247_ColonGonzalez |
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paper:paper_00219258_v283_n50_p35247_ColonGonzalez2023-06-08T14:43:29Z Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin Amines Amino acids Binding energy Binding sites Bioactivity Biochemistry Cell membranes Cytology Esterification Esters Gallium alloys Glycerol Growth (materials) Ligands Organic acids Organic compounds Peptides Pneumatic control equipment Activating proteins C1 domains Cell functions Cell migrations Diacylglycerol Epidermal growth factors In vitro Inactive conformations Ligand bindings Lipid second messengers Membrane associations Modeling analysis Neuritogenesis Phorbol esters Phospholipase Plasma membranes Protein kinases Terminal regions Chemical activation chimerin chimerin alpha 2 epidermal growth factor guanosine triphosphatase activating protein phorbol 13 acetate 12 myristate Rac protein unclassified drug article binding site cell membrane human human cell priority journal protein analysis protein domain protein function protein localization Animals Cercopithecus aethiops Chimerin 1 COS Cells Epidermal Growth Factor GTPase-Activating Proteins Hela Cells Humans Mutation Protein Binding Protein Conformation Protein Structure, Tertiary Protein Transport rac GTP-Binding Proteins Type C Phospholipases Chimaerins are a family of GTPase activating proteins (GAPs) for the small G-protein Rac that have gained recent attention due to their important roles in development, cancer, neuritogenesis, and T-cell function. Like protein kinase C isozymes, chimaerins possess a C1 domain capable of binding phorbol esters and the lipid second messenger diacylglycerol (DAG) in vitro. Here we identified an autoinhibitory mechanism in α2-chimaerin that restricts access of phorbol esters and DAG, thereby limiting its activation. Although phorbol 12-myristate 13-acetate (PMA) caused limited translocation of wild-type α2-chimaerin to the plasma membrane, deletion of either N- or C-terminal regions greatly sensitize α2-chimaerin for intracellular redistribution and activation. Based on modeling analysis that revealed an occlusion of the ligand binding site in the α2-chimaerin C1 domain, we identified key amino acids that stabilize the inactive conformation. Mutation of these sites renders α2-chimaerin hypersensitive to C1 ligands, as reflected by its enhanced ability to translocate in response to PMA and to inhibit Rac activity and cell migration. Notably, in contrast to PMA, epidermal growth factor promotes full translocation of α2-chimaerin in a phospholipase C-dependent manner, but not of a C1 domain mutant with reduced affinity for DAG (P216A-α2- chimaerin). Therefore, DAG generation and binding to the C1 domain are required but not sufficient for epidermal growth factor-induced α2-chimaerin membrane association. Our studies suggest a role for DAG in anchoring rather than activation of α2-chimaerin. Like other DAG/phorbol ester receptors, including protein kinase C isozymes, α2-chimaerin is subject to autoinhibition by intramolecular contacts, suggesting a highly regulated mechanism for the activation of this Rac-GAP. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc. 2008 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v283_n50_p35247_ColonGonzalez http://hdl.handle.net/20.500.12110/paper_00219258_v283_n50_p35247_ColonGonzalez |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
topic |
Amines Amino acids Binding energy Binding sites Bioactivity Biochemistry Cell membranes Cytology Esterification Esters Gallium alloys Glycerol Growth (materials) Ligands Organic acids Organic compounds Peptides Pneumatic control equipment Activating proteins C1 domains Cell functions Cell migrations Diacylglycerol Epidermal growth factors In vitro Inactive conformations Ligand bindings Lipid second messengers Membrane associations Modeling analysis Neuritogenesis Phorbol esters Phospholipase Plasma membranes Protein kinases Terminal regions Chemical activation chimerin chimerin alpha 2 epidermal growth factor guanosine triphosphatase activating protein phorbol 13 acetate 12 myristate Rac protein unclassified drug article binding site cell membrane human human cell priority journal protein analysis protein domain protein function protein localization Animals Cercopithecus aethiops Chimerin 1 COS Cells Epidermal Growth Factor GTPase-Activating Proteins Hela Cells Humans Mutation Protein Binding Protein Conformation Protein Structure, Tertiary Protein Transport rac GTP-Binding Proteins Type C Phospholipases |
spellingShingle |
Amines Amino acids Binding energy Binding sites Bioactivity Biochemistry Cell membranes Cytology Esterification Esters Gallium alloys Glycerol Growth (materials) Ligands Organic acids Organic compounds Peptides Pneumatic control equipment Activating proteins C1 domains Cell functions Cell migrations Diacylglycerol Epidermal growth factors In vitro Inactive conformations Ligand bindings Lipid second messengers Membrane associations Modeling analysis Neuritogenesis Phorbol esters Phospholipase Plasma membranes Protein kinases Terminal regions Chemical activation chimerin chimerin alpha 2 epidermal growth factor guanosine triphosphatase activating protein phorbol 13 acetate 12 myristate Rac protein unclassified drug article binding site cell membrane human human cell priority journal protein analysis protein domain protein function protein localization Animals Cercopithecus aethiops Chimerin 1 COS Cells Epidermal Growth Factor GTPase-Activating Proteins Hela Cells Humans Mutation Protein Binding Protein Conformation Protein Structure, Tertiary Protein Transport rac GTP-Binding Proteins Type C Phospholipases Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
topic_facet |
Amines Amino acids Binding energy Binding sites Bioactivity Biochemistry Cell membranes Cytology Esterification Esters Gallium alloys Glycerol Growth (materials) Ligands Organic acids Organic compounds Peptides Pneumatic control equipment Activating proteins C1 domains Cell functions Cell migrations Diacylglycerol Epidermal growth factors In vitro Inactive conformations Ligand bindings Lipid second messengers Membrane associations Modeling analysis Neuritogenesis Phorbol esters Phospholipase Plasma membranes Protein kinases Terminal regions Chemical activation chimerin chimerin alpha 2 epidermal growth factor guanosine triphosphatase activating protein phorbol 13 acetate 12 myristate Rac protein unclassified drug article binding site cell membrane human human cell priority journal protein analysis protein domain protein function protein localization Animals Cercopithecus aethiops Chimerin 1 COS Cells Epidermal Growth Factor GTPase-Activating Proteins Hela Cells Humans Mutation Protein Binding Protein Conformation Protein Structure, Tertiary Protein Transport rac GTP-Binding Proteins Type C Phospholipases |
description |
Chimaerins are a family of GTPase activating proteins (GAPs) for the small G-protein Rac that have gained recent attention due to their important roles in development, cancer, neuritogenesis, and T-cell function. Like protein kinase C isozymes, chimaerins possess a C1 domain capable of binding phorbol esters and the lipid second messenger diacylglycerol (DAG) in vitro. Here we identified an autoinhibitory mechanism in α2-chimaerin that restricts access of phorbol esters and DAG, thereby limiting its activation. Although phorbol 12-myristate 13-acetate (PMA) caused limited translocation of wild-type α2-chimaerin to the plasma membrane, deletion of either N- or C-terminal regions greatly sensitize α2-chimaerin for intracellular redistribution and activation. Based on modeling analysis that revealed an occlusion of the ligand binding site in the α2-chimaerin C1 domain, we identified key amino acids that stabilize the inactive conformation. Mutation of these sites renders α2-chimaerin hypersensitive to C1 ligands, as reflected by its enhanced ability to translocate in response to PMA and to inhibit Rac activity and cell migration. Notably, in contrast to PMA, epidermal growth factor promotes full translocation of α2-chimaerin in a phospholipase C-dependent manner, but not of a C1 domain mutant with reduced affinity for DAG (P216A-α2- chimaerin). Therefore, DAG generation and binding to the C1 domain are required but not sufficient for epidermal growth factor-induced α2-chimaerin membrane association. Our studies suggest a role for DAG in anchoring rather than activation of α2-chimaerin. Like other DAG/phorbol ester receptors, including protein kinase C isozymes, α2-chimaerin is subject to autoinhibition by intramolecular contacts, suggesting a highly regulated mechanism for the activation of this Rac-GAP. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc. |
title |
Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
title_short |
Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
title_full |
Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
title_fullStr |
Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
title_full_unstemmed |
Identification of an autoinhibitory mechanism that restricts C1 domain-mediated activation of the Rac-GAP α2-chimaerin |
title_sort |
identification of an autoinhibitory mechanism that restricts c1 domain-mediated activation of the rac-gap α2-chimaerin |
publishDate |
2008 |
url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v283_n50_p35247_ColonGonzalez http://hdl.handle.net/20.500.12110/paper_00219258_v283_n50_p35247_ColonGonzalez |
_version_ |
1768545080330682368 |