Abstract
Early onset dystonia is a movement disorder caused by loss of a glutamic acid residue (Glu(302/303)) in the carboxyl-terminal portion of the AAA+ protein, torsinA. We identified the light chain subunit (KLC1) of kinesin-I as an interacting partner for torsinA, with binding occurring between the tetratricopeptide repeat domain of KLC1 and the carboxyl-terminal region of torsinA. Coimmunoprecipitation analysis demonstrated that wild-type torsinA and kinesin-I form a complex in vivo. In cultured cortical neurons, both proteins co-localized along processes with enrichment at growth cones. Wild-type torsinA expressed in CAD cells co-localized with endogenous KLC1 at the distal end of processes, whereas mutant torsinA remained confined to the cell body. Subcellular fractionation of adult rat brain revealed torsinA and KLC associated with cofractionating membranes, and both proteins were co-immunoprecipitated after cross-linking cytoplasmically oriented proteins on isolated rat brain membranes. These studies suggest that wild-type torsinA undergoes anterograde transport along microtubules mediated by kinesin and may act as a molecular chaperone regulating kinesin activity and/or cargo binding.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenine / analogs & derivatives
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Adenine / metabolism
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Amino Acid Sequence
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Animals
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Biotinylation
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Brain / metabolism
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Carrier Proteins / chemistry*
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Carrier Proteins / metabolism
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Cell Line
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Cross-Linking Reagents / pharmacology
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Cytoplasm / metabolism
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Dystonia / metabolism
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Glutathione Transferase / metabolism
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Humans
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Kinesins / chemistry
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Kinetin
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Microscopy, Fluorescence
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Microtubule-Associated Proteins / chemistry*
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Microtubule-Associated Proteins / metabolism
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Molecular Chaperones / chemistry*
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Molecular Chaperones / metabolism
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Molecular Sequence Data
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Mutation
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Neurons / cytology
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Neurons / metabolism
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Plasmids / metabolism
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Precipitin Tests
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Protein Binding
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Protein Isoforms
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Protein Structure, Tertiary
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Rats
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Rats, Sprague-Dawley
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Streptavidin / pharmacology
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Subcellular Fractions / metabolism
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Transfection
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Two-Hybrid System Techniques
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beta-Galactosidase / metabolism
Substances
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Carrier Proteins
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Cross-Linking Reagents
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KLC1 protein, human
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Klc1 protein, rat
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Microtubule-Associated Proteins
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Molecular Chaperones
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Protein Isoforms
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TOR1A protein, human
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Tor1a protein, rat
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Streptavidin
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Glutathione Transferase
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beta-Galactosidase
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Kinesins
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Adenine
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Kinetin