TY - JOUR
T1 - Catastrophic disassembly of actin filaments via Mical-mediated oxidation
AU - Grintsevich, Elena E.
AU - Ge, Peng
AU - Sawaya, Michael R.
AU - Yesilyurt, Hunkar Gizem
AU - Terman, Jonathan R.
AU - Zhou, Z. Hong
AU - Reisler, Emil
N1 - Funding Information:
This project received support from National Institutes of Health grants GM077190, GM071940 and MH085923, and National Science Foundation Grant No. DMR-1548924. We acknowledge the use of instruments at the Electron Imaging Center for Nano-machines supported by UCLA and by instrumentation grants from NIH (1S10OD018111) and NSF (DBI-1338135), and the use of computer time at the Extreme Science and Engineering Discovery Environment (XSEDE) resources (MCB140140). We acknowledge National Institutes of Health grants P41 GM103403, S10 RR029205, and resources of the U.S. Department of Energy (Contract No. DE-AC02-06CH11357) for their support of the Northeastern Collaborative Access Team beamline used for crystallographic data collection.
Publisher Copyright:
© 2017 The Author(s).
PY - 2017/12/1
Y1 - 2017/12/1
N2 - Actin 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 Å 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.
AB - Actin 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 Å 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.
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U2 - 10.1038/s41467-017-02357-8
DO - 10.1038/s41467-017-02357-8
M3 - Article
C2 - 29259197
AN - SCOPUS:85038628534
SN - 2041-1723
VL - 8
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 2183
ER -