4B1U

Structure of the Phactr1 RPEL domain and RPEL motif directed assemblies with G-actin reveal the molecular basis for actin binding cooperativity.

Summary for 4B1U

• Entry DOI: 10.2210/pdb4b1u/pdb
• Related: 4B1V 4B1W 4B1X 4B1Y 4B1Z
• Descriptor: ACTIN, ALPHA SKELETAL MUSCLE, PHOSPHATASE AND ACTIN REGULATOR 1, LATRUNCULIN B, ... (8 entities in total)
• Functional Keywords: structural protein, nucleotide-binding, transcription regulation, muscle protein, atp-binding, cytoskeleton
• Biological source: ORYCTOLAGUS CUNICULUS (RABBIT); More
• Cellular location: Cytoplasm, cytoskeleton: P68134
• Total number of polymer chains: 2
• Total formula weight: 46897.47

Authors

Mouilleron, S.,Wiezlak, M.,O'Reilly, N.,Treisman, R.,McDonald, N.Q. (deposition date: 2012-07-12, release date: 2013-07-31, Last modification date: 2023-12-20)

Primary citation

Mouilleron, S.,Wiezlak, M.,O'Reilly, N.,Treisman, R.,McDonald, N.Q.
Structures of the Phactr1 RPEL domain and RPEL motif complexes with G-actin reveal the molecular basis for actin binding cooperativity.
Structure, 20:1960-1970, 2012

PubMed 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.

PubMed: 23041370
DOI: 10.1016/j.str.2012.08.031

Experimental method

X-RAY DIFFRACTION (2 Å)