1ux4
Crystal structures of a Formin Homology-2 domain reveal a tethered-dimer architecture
Structural highlights
FunctionBNI1_YEAST Required for the assembly of F-actin structures, such as actin cables and stress fibers. Nucleates actin filaments. Binds to the barbed end of the actin filament and acts as leaky capper, slowing both polymerization and depolymerization. Protects the growing actin fiber from tight capping proteins and so increases the time of elongation and the total amount of F-actin. May organize microtubules by mediating spindle positioning and movement in the budding process. Potential target of the RHO family members.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedFormin proteins participate in a wide range of cytoskeletal processes in all eukaryotes. The defining feature of formins is a highly conserved approximately 400 residue region, the Formin Homology-2 (FH2) domain, which has recently been found to nucleate actin filaments. Here we report crystal structures of the S. cerevesiae Bni1p FH2 domain. The mostly alpha-helical FH2 domain forms a unique "tethered dimer" in which two elongated actin binding heads are tied together at either end by an unusual lasso and linker structure. Biochemical and crystallographic observations indicate that the dimer is stable but flexible, with flexibility between the two halves of the dimer conferred by the linker segments. Although each half of the dimer is competent to interact with filament ends, the intact dimer is required for actin nucleation and processive capping. The tethered dimer architecture may allow formins to stair-step on the barbed end of an elongating nascent filament. Crystal structures of a Formin Homology-2 domain reveal a tethered dimer architecture.,Xu Y, Moseley JB, Sagot I, Poy F, Pellman D, Goode BL, Eck MJ Cell. 2004 Mar 5;116(5):711-23. PMID:15006353[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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