4B1X

Structure of the Phactr1 RPEL-2 bound to G-actin

Summary for 4B1X

• Entry DOI: 10.2210/pdb4b1x/pdb
• Related: 1ALM 1ATN 1EQY 1ESV 1H1V 1IJJ 1J6Z 1KXP 1LCU 1LOT 1M8Q 1MA9 1MVW 1NWK 1O18 1O19 1O1A 1O1B 1O1C 1O1D 1O1E 1O1F 1O1G 1P8Z 1QZ5 1QZ6 1RDW 1RFQ 1RGI 1S22 1SQK 1T44 1UY5 1WUA 1Y64 2A3Z 2A40 2A41 2A42 2A5X 2ASM 2ASO 2ASP 2D1K 2FF3 2FF6 2FXU 2V51 2V52 2VCP 2VYP 2W49 2W4U 2Y83 2YJE 2YJF 4A7H 4A7L 4A7N 4B1U 4B1V 4B1W 4B1Y 4B1Z
• Descriptor: ACTIN, ALPHA SKELETAL MUSCLE, PHOSPHATASE AND ACTIN REGULATOR 1, LATRUNCULIN B, ... (6 entities in total)
• Functional Keywords: structural protein, nucleotide-binding, transcription regulation, transcription, muscle protein, atp-binding, cytoskeleton
• Biological source: ORYCTOLAGUS CUNICULUS (RABBIT); More
• Total number of polymer chains: 2
• Total formula weight: 46761.16

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 (1.8 Å)