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Structural and functional studies of signaling molecules in axon guidance
Knapp, Kryštof ; Rozbeský, Daniel (advisor) ; Novák, Petr (referee)
This work aims to determine a model of the autoinhibition mechanism of MICAL proteins using biochemical, biophysical, and bioinformatical approaches. MICAL proteins are a group of flavin monooxygenases that play a key role in various cellular processes, as they facilitate the reorganization of the actin cytoskeleton. MICAL-1 has long been known for its vital role in axon guidance as an effector of repulsive signaling through oxidative destabilization of actin filaments. However, recent findings indicate that MICAL-1 can also serve as a sig- naling molecule, using localized hydrogen peroxide production to regulate other downstream effectors. Despite the consensus that MICAL-1 activity must be strictly regulated, the exact molecular mechanism of this regulation has not yet been described. In this work, we provide a novel model of MICAL-1 autoinibiton mechanism based on a comparison of steady-state kinetic experiments and molecular dynamics simulations between full-length MICAL-1 from Coturnix japonica and its truncated form lacking the C-terminal domain. In our model, we conclude that changes in MICAL-1 activity are the result of intramolecular protein interac- tions between the C-terminal and the monooxygenase domain. Furthermore, we rule out the role of MICAL-1 oligomerization in its activity...
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