8F8T

Cryo-EM structure of the Tropomodulin-capped pointed end of F-actin

Summary for 8F8T

• Entry DOI: 10.2210/pdb8f8t/pdb
• EMDB information: 28932 28933 28934 28935 28936
• Descriptor: Actin, alpha skeletal muscle, Tropomodulin-1, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: actin cytoskeleton, filament, tmod, structural protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 8
• Total formula weight: 338549.43

Authors

Carman, P.J.,Barrie, K.R.,Dominguez, R. (deposition date: 2022-11-22, release date: 2023-06-07, Last modification date: 2023-07-05)

Primary citation

Carman, P.J.,Barrie, K.R.,Rebowski, G.,Dominguez, R.
Structures of the free and capped ends of the actin filament.
Science, 380:1287-1292, 2023

PubMed Abstract: The barbed and pointed ends of the actin filament (F-actin) are the sites of growth and shrinkage and the targets of capping proteins that block subunit exchange, including CapZ at the barbed end and tropomodulin at the pointed end. We describe cryo-electron microscopy structures of the free and capped ends of F-actin. Terminal subunits at the free barbed end adopt a "flat" F-actin conformation. CapZ binds with minor changes to the barbed end but with major changes to itself. By contrast, subunits at the free pointed end adopt a "twisted" monomeric actin (G-actin) conformation. Tropomodulin binding forces the second subunit into an F-actin conformation. The structures reveal how the ends differ from the middle in F-actin and how these differences control subunit addition, dissociation, capping, and interactions with end-binding proteins.

PubMed: 37228182
DOI: 10.1126/science.adg6812

Experimental method

ELECTRON MICROSCOPY (3.26 Å)