Monooxygenase that promotes depolymerization of F-actin by mediating oxidation of specific methionine residues on actin to form methionine-sulfoxide, resulting in actin filament disassembly and preventing repolymerization. In the absence of actin, it also functions as a NADPH oxidase producing H(2)O(2). 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. Involved in regulation of lamina-specific connectivity in the nervous system such as the development of lamina-restricted hippocampal connections. Through redox regulation of the actin cytoskeleton controls the intracellular distribution of secretory vesicles containing L1/neurofascin/NgCAM family proteins in neurons, thereby regulating their cell surface levels. May act as Rab effector protein and play a role in vesicle trafficking. H(+) + L-methionyl-[F-actin] + NADPH + O2 = H2O + L-methionyl-(R)-S-oxide-[F-actin] + NADP(+) H(+) + NADPH + O2 = H2O2 + NADP(+) Interacts with STK38 and STK38L. Associates with the SH3 domain of NEDD9. Interacts with VIM and PLXNA3. Interacts with RAB1B, RAB8A, RAB10, RAB13 and RAB15 (in their GTP-bound forms); binding to RAB1B is of low affinity compared to other Rab proteins; at least in case of RAB8A and RAB10 can bind 2 molecules of the Rab proteins simultaneously. The bivalent Mical/EHBP Rab binding (bMERB) domain, mediates binding to predominantly Rab8, Rab10, Rab10, Rab13 and Rab15 (in their GTP-bound forms). The C-terminal coiled coil part contains the plexin-interacting region. Belongs to the Mical family. The reaction mechanism is subject to discussion. Some work suggest MICAL enzymes directly oxidize actin methionine residues to produce methionine-(R)-S-oxide. Other publications suggest that the enzyme functions as a NADPH oxidase producing H(2)O(2) (EC 1.6.3.1) and that it is the produced H(2)O(2) that is responsible for the methionine-(R)-S-oxide production.