Serine 970 of RNA helicase MOV10 is phosphorylated and controls unfolding activity and fate of mRNAs targeted for AGO2-mediated silencing.

MOV10 is an RNA helicase required for organismal development and is highly expressed in postnatal brain. MOV10 is an AGO2-associated protein that is also necessary for AGO2-mediated silencing. AGO2 is the primary effector of the miRNA pathway. MOV10 has been shown to be ubiquitinated, leading to its degradation and release from bound mRNAs, but no other posttranslational modifications with functional implications have been described. Using mass spectrometry, we show that MOV10 is phosphorylated in cells at the C-terminus, specifically at serine 970 (S970). Substitution of S970 to phospho-mimic aspartic acid (S970D) blocked unfolding of an RNA G-quadruplex, similar to when the helicase domain was mutated (K531A). In contrast, the alanine substitution (S970A) of MOV10 unfolded the model RNA G-quadruplex. To examine its role in cells, our RNA-seq analysis showed that the expression of S970D causes decreased expression of MOV10 enhanced Cross-Linking Immunoprecipitation targets compared to WT. Introduction of S970A had an intermediate effect, suggesting that S970 was protective of mRNAs. In whole-cell extracts, MOV10 and its substitutions bound AGO2 comparably; however, knockdown of AGO2 abrogated the S970D-induced mRNA degradation. Thus, MOV10 activity protects mRNA from AGO2; phosphorylation of S970 restricts this activity resulting in AGO2-mediated mRNA degradation. S970 is positioned C-terminal to the defined MOV10-AGO2 interaction site and is proximal to a disordered region that likely modulates AGO2 interaction with target mRNAs upon phosphorylation. In summary, we provide evidence whereby MOV10 phosphorylation facilitates AGO2 association with the 3'UTR of translating mRNAs that leads to their degradation.

The FMRP-MOV10 complex: a translational regulatory switch modulated by G-Quadruplexes.

The Fragile X Mental Retardation Protein (FMRP) is an RNA binding protein that regulates translation and is required for normal cognition. FMRP upregulates and downregulates the activity of microRNA (miRNA)-mediated silencing in the 3' UTR of a subset of mRNAs through its interaction with RNA helicase Moloney leukemia virus 10 (MOV10). This bi-functional role is modulated through RNA secondary structures known as G-Quadruplexes. We elucidated the mechanism of FMRP's role in suppressing Argonaute (AGO) family members' association with mRNAs by mapping the interacting domains of FMRP, MOV10 and AGO and then showed that the RGG box of FMRP protects a subset of co-bound mRNAs from AGO association. The N-terminus of MOV10 is required for this protection: its over-expression leads to increased levels of the endogenous proteins encoded by this co-bound subset of mRNAs. The N-terminus of MOV10 also leads to increased RGG box-dependent binding to the SC1 RNA G-Quadruplex and is required for outgrowth of neurites. Lastly, we showed that FMRP has a global role in miRNA-mediated translational regulation by recruiting AGO2 to a large subset of RNAs in mouse brain.

Mov10 suppresses retroelements and regulates neuronal development and function in the developing brain.

BACKGROUND: Moloney leukemia virus 10 (Mov10) is an RNA helicase that mediates access of the RNA-induced silencing complex to messenger RNAs (mRNAs). Until now, its role as an RNA helicase and as a regulator of retrotransposons has been characterized exclusively in cell lines. We investigated the role of Mov10 in the mouse brain by examining its expression over development and attempting to create a Mov10 knockout mouse. Loss of both Mov10 copies led to early embryonic lethality. RESULTS: Mov10 was significantly elevated in postnatal murine brain, where it bound retroelement RNAs and mRNAs. Mov10 suppressed retroelements in the nucleus by directly inhibiting complementary DNA synthesis, while cytosolic Mov10 regulated cytoskeletal mRNAs to influence neurite outgrowth. We verified this important function by observing reduced dendritic arborization in hippocampal neurons from the Mov10 heterozygote mouse and shortened neurites in the Mov10 knockout Neuro2A cells. Knockdown of Fmrp also resulted in shortened neurites. Mov10, Fmrp, and Ago2 bound a common set of mRNAs in the brain. Reduced Mov10 in murine brain resulted in anxiety and increased activity in a novel environment, supporting its important role in the development of normal brain circuitry. CONCLUSIONS: Mov10 is essential for normal neuronal development and brain function. Mov10 preferentially binds RNAs involved in actin binding, neuronal projection, and cytoskeleton. This is a completely new and critically important function for Mov10 in neuronal development and establishes a precedent for Mov10 being an important candidate in neurological disorders that have underlying cytoarchitectural causes like autism and Alzheimer's disease.

MOV10 and FMRP regulate AGO2 association with microRNA recognition elements.

The fragile X mental retardation protein FMRP regulates translation of its bound mRNAs through incompletely defined mechanisms. FMRP has been linked to the microRNA pathway, and we show here that it associates with the RNA helicase MOV10, also associated with the microRNA pathway. FMRP associates with MOV10 directly and in an RNA-dependent manner and facilitates MOV10's association with RNAs in brain and cells, suggesting a cooperative interaction. We identified the RNAs recognized by MOV10 using RNA immunoprecipitation and iCLIP. Examination of the fate of MOV10 on RNAs revealed a dual function for MOV10 in regulating translation: it facilitates microRNA-mediated translation of some RNAs, but it also increases expression of other RNAs by preventing AGO2 function. The latter subset was also bound by FMRP in close proximity to the MOV10 binding site, suggesting that FMRP prevents MOV10-mediated microRNA suppression. We have identified a mechanism for FMRP-mediated translational regulation through its association with MOV10.

Intubación endotraqueal con broncoscopio fibróptico flexible en paciente con bocio no tóxico severo / Endotracheal intubation with flexible fiberoptic bronchoscope in patients with severe nontoxic goiter

Introducción: los pacientes con bocio severo no tóxico pueden manifestar síntomas obstructivos de la vía aérea con implicaciones importantes para la conducta anestesiológica. El uso del broncoscopio flexible es la alternativa de primera línea para la intubación endotraqueal de estos enfermos.Paciente: mujer de 34 años con bocio severo que ingresó para exéresis quirúrgica de un nódulo frío en el polo inferior del lóbulo derecho del tiroides. Se intubó la tráquea con el uso de un broncoscopio flexible mientras se mantuvo respirando espontáneamente, sedada con una infusión continua de dexmedetomidina. Conclusiones: la intubación fibróptica se considera el «patrón de oro¼ para el abordaje de la vía aérea difícil anticipada. El estudio y la práctica de esta técnica por el anestesiólogo resultan una necesidad perentoria(AU)

Background: Patients with severe nontoxic goiter can present obstructive symptoms of the airways with important implications for the anaesthesiology behaviour. The use of the flexible fiberoptic bronchoscope is a first line alternative for the endotracheal intubation in these patients. Patient: 34-year-old woman suffering from severe goiter who was atmitted to hospital to undergo a surgical exerecis of a cold nodule located in the lower pole of the right lobe of the thyroid gland. The trachea was intubated using a flexible bronchoscope while she was breathing spontaneously and sedated with a continuous infusion of Dexmedetomidine. Conclusions: The fiberoptic intubation is considered "the gold pattern" for the approach of the anticipated difficult airway. The study and practice of this technique by the anaesthesiologist constitute an urgent need(AU)

Intubación endotraqueal con broncoscopio fibróptico flexible en paciente con bocio no tóxico severo / Endotracheal intubation with flexible fiberoptic bronchoscope in patients with severe nontoxic goiter

Introducción: Los pacientes con bocio severo no tóxico pueden manifestar síntomas obstructivos de la vía aérea con implicaciones importantes para la conducta anestesiológica. El uso del broncoscopio flexible es la alternativa de primera línea para la intubación endotraqueal de estos enfermos. Paciente: Mujer de 34 años con bocio severo que ingresó para exéresis quirúrgica de un nódulo frío en el polo inferior del lóbulo derecho del tiroides. Se intubó la tráquea con el uso de un broncoscopio flexible mientras se mantuvo respirando espontáneamente, sedada con una infusión continua de dexmedetomidina. Conclusiones: La intubación fibróptica se considera el «patrón de oro¼ para el abordaje de la vía aérea difícil anticipada. El estudio y la práctica de esta técnica por el anestesiólogo resultan una necesidad perentoria.

Background: Patients with severe nontoxic goiter can present obstructive symptoms of the airways with important implications for the anaesthesiology behaviour. The use of the flexible fiberoptic bronchoscope is a first line alternative for the endotracheal intubation in these patients. Patient: 34-year-old woman suffering from severe goiter who was atmitted to hospital to undergo a surgical exerecis of a cold nodule located in the lower pole of the right lobe of the thyroid gland. The trachea was intubated using a flexible bronchoscope while she was breathing spontaneously and sedated with a continuous infusion of Dexmedetomidine. Conclusions: The fiberoptic intubation is considered "the gold pattern" for the approach of the anticipated difficult airway. The study and practice of this technique by the anaesthesiologist constitute an urgent need.