4yc7
From Proteopedia
Crystal structure of human FMNL2 GBD-FH3 Domains bound to Cdc42-GppNHp
Structural highlights
Function[FMNL2_HUMAN] Plays a role in the regulation of cell morphology and cytoskeletal organization. Required in the cortical actin filament dynamics.[1] [CDC42_HUMAN] Plasma membrane-associated small GTPase which cycles between an active GTP-bound and an inactive GDP-bound state. In active state binds to a variety of effector proteins to regulate cellular responses. Involved in epithelial cell polarization processes. Regulates the bipolar attachment of spindle microtubules to kinetochores before chromosome congression in metaphase. Plays a role in the extension and maintenance of the formation of thin, actin-rich surface projections called filopodia. Mediates CDC42-dependent cell migration.[2] [3] [4] Publication Abstract from PubMedFormins are actin polymerization factors that elongate unbranched actin filaments at the barbed end. Rho family GTPases activate Diaphanous-related formins through the relief of an autoregulatory interaction. The crystal structures of the N-terminal domains of human FMNL1 and FMNL2 in complex with active Cdc42 show that Cdc42 mediates contacts with all five armadillo repeats of the formin with specific interactions formed by the Rho-GTPase insert helix. Mutation of three residues within Rac1 results in a gain-of-function mutation for FMNL2 binding and reconstitution of the Cdc42 phenotype in vivo. Dimerization of FMNL1 through a parallel coiled coil segment leads to formation of an umbrella-shaped structure that-together with Cdc42-spans more than 15 nm in diameter. The two interacting FMNL-Cdc42 heterodimers expose six membrane interaction motifs on a convex protein surface, the assembly of which may facilitate actin filament elongation at the leading edge of lamellipodia and filopodia. The structure of FMNL2-Cdc42 yields insights into the mechanism of lamellipodia and filopodia formation.,Kuhn S, Erdmann C, Kage F, Block J, Schwenkmezger L, Steffen A, Rottner K, Geyer M Nat Commun. 2015 May 12;6:7088. doi: 10.1038/ncomms8088. PMID:25963737[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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