5I9E

Crystal structure of a nuclear actin ternary complex

Summary for 5I9E

• Entry DOI: 10.2210/pdb5i9e/pdb
• Descriptor: Actin-related protein 4, Actin, Helicase SWR1, ... (5 entities in total)
• Functional Keywords: nuclear actin, arp4, chromatin remodeling, hydrolase
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast); More
• Total number of polymer chains: 6
• Total formula weight: 213015.35

Authors

Chen, Z.,Cao, T. (deposition date: 2016-02-20, release date: 2016-07-27, Last modification date: 2023-11-08)

Primary citation

Cao, T.,Sun, L.,Jiang, Y.,Huang, S.,Wang, J.,Chen, Z.
Crystal structure of a nuclear actin ternary complex.
Proc.Natl.Acad.Sci.USA, 113:8985-8990, 2016

PubMed Abstract: Actin polymerizes and forms filamentous structures (F-actin) in the cytoplasm of eukaryotic cells. It also exists in the nucleus and regulates various nucleic acid transactions, particularly through its incorporation into multiple chromatin-remodeling complexes. However, the specific structure of actin and the mechanisms that regulate its polymeric nature inside the nucleus remain unknown. Here, we report the crystal structure of nuclear actin (N-actin) complexed with actin-related protein 4 (Arp4) and the helicase-SANT-associated (HSA) domain of the chromatin remodeler Swr1. The inner face and barbed end of N-actin are sequestered by interactions with Arp4 and the HSA domain, respectively, which prevents N-actin from polymerization and binding to many actin regulators. The two major domains of N-actin are more twisted than those of globular actin (G-actin), and its nucleotide-binding pocket is occluded, freeing N-actin from binding to and regulation by ATP. These findings revealed the salient structural features of N-actin that distinguish it from its cytoplasmic counterpart and provide a rational basis for its functions and regulation inside the nucleus.

PubMed: 27457955
DOI: 10.1073/pnas.1602818113

Experimental method

X-RAY DIFFRACTION (2.8 Å)