Developmental remodeling shapes neural circuits via activity-dependent pruning of synapses and axons. Regulation of the cytoskeleton is critical for this process, as microtubule loss via enzymatic severing is an early step of pruning across many circuits and species. However, how microtubule-severing enzymes, such as spastin, are activated in specific neuronal compartments remains unknown. Here, we reveal that polyglutamylation, a post-translational tubulin modification enriched in neurons, plays an instructive role in developmental remodeling by tagging microtubules for severing. Motor neuron-specific gene deletion of enzymes that add or remove tubulin polyglutamylation-TTLL glutamylases vs. CCP deglutamylases-accelerates or delays neuromuscular synapse remodeling in a neurotransmission-dependent manner. This mechanism is not specific to peripheral synapses but also operates in central circuits, e.g., the hippocampus. Thus, tubulin polyglutamylation acts as a cytoskeletal rheostat of remodeling that shapes neuronal morphology and connectivity.

• MeSH
• Hippocampus metabolism   cytology   MeSH
• Polyglutamic Acid * metabolism   MeSH
• Microtubules * metabolism   MeSH
• Motor Neurons * metabolism   MeSH
• Mice MeSH
• Neuromuscular Junction metabolism   MeSH
• Synaptic Transmission MeSH
• Neurons * metabolism   MeSH
• Neuronal Plasticity * physiology   MeSH
• Peptide Synthases metabolism   genetics   MeSH
• Protein Processing, Post-Translational MeSH
• Spastin metabolism   MeSH
• Synapses metabolism   MeSH
• Tubulin metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Polyglutamic Acid * MeSH
• Peptide Synthases MeSH
• Spastin MeSH
• tubulin polyglutamylase MeSH Browser
• Tubulin MeSH

Amyotrophic lateral sclerosis (ALS) is a fatal non-cell-autonomous neurodegenerative disease characterized by the loss of motor neurons (MNs). Mutations in CRMP4 are associated with ALS in patients, and elevated levels of CRMP4 are suggested to affect MN health in the SOD1G93A -ALS mouse model. However, the mechanism by which CRMP4 mediates toxicity in ALS MNs is poorly understood. Here, by using tissue from human patients with sporadic ALS, MNs derived from C9orf72-mutant patients, and the SOD1G93A -ALS mouse model, we demonstrate that subcellular changes in CRMP4 levels promote MN loss in ALS. First, we show that while expression of CRMP4 protein is increased in cell bodies of ALS-affected MN, CRMP4 levels are decreased in the distal axons. Cellular mislocalization of CRMP4 is caused by increased interaction with the retrograde motor protein, dynein, which mediates CRMP4 transport from distal axons to the soma and thereby promotes MN loss. Blocking the CRMP4-dynein interaction reduces MN loss in human-derived MNs (C9orf72) and in ALS model mice. Thus, we demonstrate a novel CRMP4-dependent retrograde death signal that underlies MN loss in ALS.

• Keywords
• ALS, CRMP4, axonal transport, dynein, retrograde signaling,
• MeSH
• Amyotrophic Lateral Sclerosis genetics   metabolism   MeSH
• Axonal Transport * MeSH
• Axons metabolism   MeSH
• Cell Death MeSH
• Cell Line MeSH
• Dyneins metabolism   MeSH
• Cells, Cultured MeSH
• Motor Neurons metabolism   pathology   MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Nerve Tissue Proteins genetics   metabolism   MeSH
• Signal Transduction MeSH
• Superoxide Dismutase-1 genetics   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Dpysl3 protein, mouse MeSH Browser
• Dyneins MeSH
• Nerve Tissue Proteins MeSH
• Sod1 protein, mouse MeSH Browser
• Superoxide Dismutase-1 MeSH

Autism spectrum disorder (ASD) is a heterogeneous condition with multiple etiologies and risk factors - both genetic and environmental. Recent data demonstrate that the immune system plays an important role in prenatal brain development. Deregulation of the immune system during embryonic development can lead to neurodevelopmental changes resulting in ASD. One of the potential etiologic factors in the development of ASD has been identified as the presence of maternal autoantibodies targeting fetal brain proteins. The type of ASD associated with the presence of maternal autoantibodies has been referred to as maternal antibodies related to ASD (MAR ASD). The link between maternal autoantibodies and ASD has been demonstrated in both clinical studies and animal models, but the exact mechanism of their action in the pathogenesis of ASD has not been clarified yet. Several protein targets of ASD-related maternal autoantibodies have been identified. Here, we discuss the role of microtubule-associated proteins of the collapsin response mediator protein (CRMP) family in neurodevelopment and ASD. CRMPs have been shown to integrate multiple signaling cascades regulating neuron growth, guidance or migration. Their targeting by maternal autoantibodies could change CRMP levels or distribution in the developing nervous system, leading to defects in axon growth/guidance, cortical migration, or dendritic projection, which could play an etiological role in ASD development. In addition, we discuss the future possibilities of MAR ASD treatment.

• Keywords
• CRMP2, animal models, autism spectrum disorder, maternal autoantibodies, therapy,
• Publication type
• Journal Article MeSH
• Review MeSH