PDBsum entry 4eah

Protein binding

PDB id: 4eah

Contents

Protein chains

356 a.a.

357 a.a.

Ligands

ACT ×12

ATP ×4

References listed in PDB file

Key reference

• Title: Fmnl3 fh2-Actin structure gives insight into formin-Mediated actin nucleation and elongation.
• Authors: M.E.Thompson, E.G.Heimsath, T.J.Gauvin, H.N.Higgs, F.J.Kull.
• Ref.: Nat Struct Biol, 2013, 20, 111-118.
• PubMed id: 23222643

Abstract

Formins are actin-assembly factors that act in a variety of actin-based processes. The conserved formin homology 2 (FH2) domain promotes filament nucleation and influences elongation through interaction with the barbed end. FMNL3 is a formin that induces assembly of filopodia but whose FH2 domain is a poor nucleator. The 3.4-Å structure of a mouse FMNL3 FH2 dimer in complex with tetramethylrhodamine-actin uncovers details of formin-regulated actin elongation. We observe distinct FH2 actin-binding regions; interactions in the knob and coiled-coil subdomains are necessary for actin binding, whereas those in the lasso-post interface are important for the stepping mechanism. Biochemical and cellular experiments test the importance of individual residues for function. This structure provides details for FH2-mediated filament elongation by processive capping and supports a model in which C-terminal non-FH2 residues of FMNL3 are required to stabilize the filament nucleus.