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Amyotrophic lateral sclerosis (ALS) is a late-onset neurological disorder characterized by death of motoneurons. Mutations in Cu/Zn superoxide dismutase-1 (SOD1) cause familial ALS but the mechanisms whereby they induce disease are not fully understood. Here, we use time-lapse microscopy to monitor for the first time the effect of mutant SOD1 on fast axonal(More)
Neurofilaments possess side arms that comprise the carboxy-terminal domains of neurofilament middle and heavy chains (NFM and NFH); that of NFH is heavily phosphorylated in axons. Here, we demonstrate that phosphorylation of NFH side arms is a mechanism for regulating transport of neurofilaments through axons. Mutants in which known NFH phosphorylation(More)
Neurofilaments are transported through axons by slow axonal transport. Abnormal accumulations of neurofilaments are seen in several neurodegenerative diseases, and this suggests that neurofilament transport is defective. Excitotoxic mechanisms involving glutamate are believed to be part of the pathogenic process in some neurodegenerative diseases, but there(More)
The neuronal cyclin-dependent kinase p35/cdk5 comprises a catalytic subunit (cdk5) and an activator subunit (p35). To identify novel p35/cdk5 substrates, we utilized the yeast two-hybrid system to screen for human p35 binding partners. From one such screen, we identified beta-catenin as an interacting protein. Confirmation that p35 binds to beta-catenin was(More)
Threonine(668) (thr(668)) within the carboxy-terminus of the Alzheimer's disease amyloid precursor protein (APP) is a known in vivo phosphorylation site. Phosphorylation of APPthr(668) is believed to regulate APP function and metabolism. Thr(668) precedes a proline, which suggests that it is targeted for phosphorylation by proline-directed kinase(s). We(More)
Neurofilaments comprise three subunit proteins; neurofilament light, middle and heavy chains (NF-L, NF-M and NF-H). The carboxy-terminal domains of NF-M and NF-H form side-arms that project from the filament and that of NF-H contains multiple repeats of the motif lys-ser-pro, the serines of which are targets for phosphorylation. The level of phosphorylation(More)
Charcot-Marie-Tooth disease (CMT) is the most common inherited disorder of the peripheral nervous system, and mutations in neurofilaments have been linked to some forms of CMT. Neurofilaments are the major intermediate filaments of neurones, but the mechanisms by which the CMT mutations induce disease are not known. Here, we demonstrate that CMT mutant(More)
Rac and its downstream effectors p21-activated kinase (PAK) family kinases regulate actin dynamics within growth cones to control neurite outgrowth during development. The activity of Rac is stimulated by guanine nucleotide exchange factors (GEFs) that promote GDP release and GTP binding. ALS2/Alsin is a recently described GEF that contains a central domain(More)
Neurofilaments are among the most abundant organelles in neurones. They are synthesised in cell bodies and then transported into and through axons by a process termed 'slow axonal transport' at a rate that is distinct from that driven by conventional fast motors. Several recent studies have now demonstrated that this slow rate of transport is actually the(More)
Neurofilament middle and heavy chains (NFM and NFH) are heavily phosphorylated on their carboxy-terminal side-arm domains in axons. The mechanisms that regulate this phosphorylation are complex. Here, we demonstrate that p38alpha, a member of the stress-activated protein kinase family, will phosphorylate NFM and NFH on their side-arm domains. Aberrant(More)