Multiple Interactions between Transmembrane Helices Generate the Oligomeric α1b-Adrenoceptor
| Autor: | Graeme Milligan, Juan F. López-Giménez, Juan J. Carrillo |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Pharmacology
Mutation biology Immunoprecipitation Chemistry Stereochemistry Membrane Proteins Sequence (biology) medicine.disease_cause Protein Structure Secondary Protein Structure Tertiary Transmembrane domain Förster resonance energy transfer Rhodopsin Cricetinae Receptors Adrenergic alpha-1 Helix medicine biology.protein Animals Humans Molecular Medicine Protein quaternary structure Dimerization Cells Cultured |
| Zdroj: | Molecular Pharmacology. 66:1123-1137 |
| ISSN: | 1521-0111 0026-895X |
| Popis: | Combinations of coimmunoprecipitation, single-cell fluorescence resonance energy transfer, and cell-surface time-resolved fluorescence resonance energy transfer demonstrated protein-protein interactions and quaternary structure for the alpha(1b)-adrenoceptor. Self-association of transmembrane domain 1 and its interaction with the full-length receptor indicated a symmetrical interface provided by this domain. Lack of effect of mutation of the glycophorin-A dimerization-like region within this helix demonstrated that this did not provide the molecular mechanism. Multiple interactions were observed between the alpha(1b)-adrenoceptor and fragments derived from its sequence. Fragments comprising transmembrane domains 3 and 4 and transmembrane domains 5 and 6, but not transmembrane domain 7, were also able to interact with the full-length receptor. Transmembrane domain 7 failed to interact significantly with any element of the receptor and was not transported to the cell surface after coexpression with the full-length receptor. Symmetrical interactions were also noted between fragments incorporating transmembrane domain 4, but this segment of the receptor failed to interact with transmembrane domains 1 and 2 or transmembrane domains 5 and 6. Time-resolved fluorescence resonance energy transfer studies were also consistent with contributions of transmembrane domains 1 and/or 2 and transmembrane domains 3 and/or 4 to protein-protein interactions within the quaternary structure of the alpha(1b)-adrenoceptor, and with a contribution of transmembrane domains 5 and/or 6. These data are consistent with a complex oligomeric quaternary structure of the alpha(1b)-adrenoceptor in which major, symmetrical interactions may define intradimeric contacts with other contributions, providing interdimer contacts to generate oligomeric complexes akin to those observed for murine rhodopsin. A model derived from this was developed. |
| Databáze: | OpenAIRE |
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