1. Mechanism of Activity-Dependent Cargo Loading via the Phosphorylation of KIF3A by PKA and CaMKIIa
- Author
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Tadayuki Ogawa, Sotaro Ichinose, and Nobutaka Hirokawa
- Subjects
Dendritic spine ,Time Factors ,Neuroscience(all) ,Kinesins ,Mice, Transgenic ,macromolecular substances ,Tetrodotoxin ,Biology ,Gene Expression Regulation, Enzymologic ,Mice ,Adenosine Triphosphate ,Downregulation and upregulation ,Animals ,Anesthetics, Local ,Enzyme Inhibitors ,Phosphorylation ,Neurons ,Kinase ,General Neuroscience ,Vesicle ,Mutagenesis ,Brain ,Transporter ,Cadherins ,Cyclic AMP-Dependent Protein Kinases ,Peptide Fragments ,Cell biology ,Luminescent Proteins ,Protein Transport ,Gene Expression Regulation ,Synaptic plasticity ,Synapses ,Calcium ,Calcium-Calmodulin-Dependent Protein Kinase Type 2 - Abstract
SummaryA regulated mechanism of cargo loading is crucial for intracellular transport. N-cadherin, a synaptic adhesion molecule that is critical for neuronal function, must be precisely transported to dendritic spines in response to synaptic activity and plasticity. However, the mechanism of activity-dependent cargo loading remains unclear. To elucidate this mechanism, we investigated the activity-dependent transport of N-cadherin via its transporter, KIF3A. First, by comparing KIF3A-bound cargo vesicles with unbound KIF3A, we identified critical KIF3A phosphorylation sites and specific kinases, PKA and CaMKIIa, using quantitative phosphoanalyses. Next, mutagenesis and kinase inhibitor experiments revealed that N-cadherin transport was enhanced via phosphorylation of the KIF3A C terminus, thereby increasing cargo-loading activity. Furthermore, N-cadherin transport was enhanced during homeostatic upregulation of synaptic strength, triggered by chronic inactivation by TTX. We propose the first model of activity-dependent cargo loading, in which phosphorylation of the KIF3A C terminus upregulates the loading and transport of N-cadherin in homeostatic synaptic plasticity.
- Published
- 2015