Mechanism of Activity-Dependent Cargo Loading via the Phosphorylation of KIF3A by PKA and CaMKIIa.
A 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.
Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Sotaro
S
Ichinose
Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Tadayuki
T
Ogawa
Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Center of Excellence in Genome Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Electronic address: hirokawa@m.u-tokyo.ac.jp.
Nobutaka
N
Hirokawa
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000166:cytology*; D015820:Cadherins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000502:physiology*; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010766:Phosphorylation / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D000779:Anesthetics, Local; D015820:Cadherins; D004791:Enzyme Inhibitors; C490202:Kif3a protein, mouse; D008164:Luminescent Proteins; D010446:Peptide Fragments; D013779:Tetrodotoxin; D000255:Adenosine Triphosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D016547:Kinesins; D002118:Calcium