8y6k
From Proteopedia
Cryo-EM structure of full-length MICAL1 in the autoinhibited state
Structural highlights
FunctionMICA1_HUMAN Monooxygenase that promotes depolymerization of F-actin by mediating oxidation of specific methionine residues on actin. Acts by modifying actin subunits through the addition of oxygen to form methionine-sulfoxide, leading to promote actin filament severing and prevent repolymerization (Probable). Acts as a cytoskeletal regulator that connects NEDD9 to intermediate filaments. Also acts as a negative regulator of apoptosis via its interaction with STK38 and STK38L; acts by antagonizing STK38 and STK38L activation by MST1/STK4.[1] [2] Publication Abstract from PubMedMICAL proteins represent a unique family of actin regulators crucial for synapse development, membrane trafficking, and cytokinesis. Unlike classical actin regulators, MICALs catalyze the oxidation of specific residues within actin filaments to induce robust filament disassembly. The potent activity of MICALs requires tight control to prevent extensive damage to actin cytoskeleton. However, the molecular mechanism governing MICALs' activity regulation remains elusive. Here, we report the cryo-EM structure of MICAL1 in the autoinhibited state, unveiling a head-to-tail interaction that allosterically blocks enzymatic activity. The structure also reveals the assembly of C-terminal domains via a tripartite interdomain interaction, stabilizing the inhibitory conformation of the RBD. Our structural, biochemical, and cellular analyses elucidate a multi-step mechanism to relieve MICAL1 autoinhibition in response to the dual-binding of two Rab effectors, revealing its intricate activity regulation mechanisms. Furthermore, our mutagenesis study of MICAL3 suggests the conserved autoinhibition and relief mechanisms among MICALs. Autoinhibition and relief mechanisms for MICAL monooxygenases in F-actin disassembly.,Lin L, Dong J, Xu S, Xiao J, Yu C, Niu F, Wei Z Nat Commun. 2024 Aug 9;15(1):6824. doi: 10.1038/s41467-024-50940-7. PMID:39122694[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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