Mouilleron, S. and Wiezlak, M. and O’Reilly, N. and Treisman, R. and McDonald, Neil Q. (2012) Structures of the Phactr1 RPEL domain and RPEL motif complexes with G-Actin reveal the molecular basis for Actin Binding Cooperativity. Structure 20 (11), pp. 1960-1970. ISSN 0969-2126.
Abstract
The Phactr family of PP1-binding proteins and the myocardin-related transcription factor family of transcriptional coactivators contain regulatory domains comprising three copies of the RPEL motif, a G-actin binding element. We report the structure of a Phactr1 G-actin⋅RPEL domain complex. Three G-actins surround the crank-shaped RPEL domain forming a closed helical assembly. Their spatial relationship is identical to the RPEL-actins within the pentavalent MRTF G-actin⋅RPEL domain complex, suggesting that conserved cooperative interactions between actin⋅RPEL units organize the assembly. In the trivalent Phactr1 complex, each G-actin⋅RPEL unit makes secondary contacts with its downstream actin involving distinct RPEL residues. Similar secondary contacts are seen in G-actin⋅RPEL peptide crystals. Loss-of-secondary-contact mutations destabilize the Phactr1 G-actin⋅RPEL assembly. Furthermore, actin-mediated inhibition of Phactr1 nuclear import requires secondary contact residues in the Phactr1 N-terminal RPEL-N motif, suggesting that it involves interaction of RPEL-N with the C-terminal assembly. Secondary actin contacts by actin-bound RPEL motifs thus govern formation of multivalent actin⋅RPEL assemblies.
Metadata
| Item Type: | Article |
|---|---|
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Research Centres and Institutes: | Structural Molecular Biology, Institute of (ISMB) |
| Depositing User: | Administrator |
| Date Deposited: | 18 Oct 2012 11:22 |
| Last Modified: | 02 Aug 2023 16:59 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/5303 |
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