Structural highlights
Function[ACTS_RABIT] Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. Publication Abstract from PubMedActin filament assembly and disassembly are vital for cell functions. MICAL Redox enzymes are important post-translational effectors of actin that stereo-specifically oxidize actin's M44 and M47 residues to induce cellular F-actin disassembly. Here we show that Mical-oxidized (Mox) actin can undergo extremely fast (84 subunits/s) disassembly, which depends on F-actin's nucleotide-bound state. Using near-atomic resolution cryoEM reconstruction and single filament TIRF microscopy we identify two dynamic and structural states of Mox-actin. Modeling actin's D-loop region based on our 3.9 A cryoEM reconstruction suggests that oxidation by Mical reorients the side chain of M44 and induces a new intermolecular interaction of actin residue M47 (M47-O-T351). Site-directed mutagenesis reveals that this interaction promotes Mox-actin instability. Moreover, we find that Mical oxidation of actin allows for cofilin-mediated severing even in the presence of inorganic phosphate. Thus, in conjunction with cofilin, Mical oxidation of actin promotes F-actin disassembly independent of the nucleotide-bound state. Catastrophic disassembly of actin filaments via Mical-mediated oxidation.,Grintsevich EE, Ge P, Sawaya MR, Yesilyurt HG, Terman JR, Zhou ZH, Reisler E Nat Commun. 2017 Dec 19;8(1):2183. doi: 10.1038/s41467-017-02357-8. PMID:29259197[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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