The alpha subunits of Gz and Gi interact with the eyes absent transcription cofactor Eya2, preventing its interaction with the six class of homeodomain-containing proteins.
Yeast two-hybrid techniques were used to identify possible effectors for the heterotrimeric G protein G(z) in human bone marrow cells. Eya2, a human homologue of the Drosophila Eya transcription co-activator, was identified. Eya2 interacts with activated Galpha(z) and at least one other member of the Galpha(i) family, Galpha(i2). Interactions were confirmed in mammalian two-hybrid and glutathione S-transferase fusion protein pull-down assays. Regions of Eya2-mediating interaction were mapped to the C-terminal Eya consensus domain. Eya2 is an intrinsically cytosolic protein that is translocated to the nucleus by members of the Six homeodomain-containing family of proteins. Activated Galpha(z) and Galpha(i2) prevent Eya2 translocation and inhibit Six/Eya2-mediated activation of a reporter gene controlled through the MEF3/TATA promoter. Although G proteins are known to regulate the activity of numerous transcription factors, this regulation is normally achieved indirectly via one or more intermediates. We show here a novel functional regulation of a co-activator directly by G protein subunits.
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Departments of Pharmacology, Medicine and Pathology, and Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Brass
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Poncz
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Spitz
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Maire
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Manning
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D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D016384:Consensus Sequence; D003600:Cytosol / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter / Q000235:genetics; D006367:HeLa Cells; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D021122:Protein Subunits; D021381:Protein Transport; D017027:Protein Tyrosine Phosphatases; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D018398:Homeodomain Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; C099236:SIX1 protein, human; C490851:SIX4 protein, human; C490947:Six1 protein, mouse; D015534:Trans-Activators; C106938:EYA2 protein, human; C501159:Eya2 protein, mouse; D017027:Protein Tyrosine Phosphatases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins