Mechanism of Activity-Dependent Cargo Loading via the Phosphorylation of KIF3A by PKA and CaMKIIa

Neuron. 2015 Sep 2;87(5):1022-35. doi: 10.1016/j.neuron.2015.08.008.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Anesthetics, Local / pharmacology
  • Animals
  • Brain / cytology*
  • Cadherins / metabolism*
  • Calcium / metabolism
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / genetics
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology
  • Gene Expression Regulation, Enzymologic / genetics
  • Gene Expression Regulation, Enzymologic / physiology*
  • Kinesins / genetics
  • Kinesins / metabolism*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Mice
  • Mice, Transgenic
  • Neurons / metabolism*
  • Peptide Fragments / metabolism
  • Phosphorylation / genetics
  • Protein Transport / drug effects
  • Protein Transport / physiology
  • Synapses / drug effects
  • Synapses / metabolism
  • Tetrodotoxin / pharmacology
  • Time Factors

Substances

  • Anesthetics, Local
  • Cadherins
  • Enzyme Inhibitors
  • Kif3a protein, mouse
  • Luminescent Proteins
  • Peptide Fragments
  • Tetrodotoxin
  • Adenosine Triphosphate
  • Cyclic AMP-Dependent Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Kinesins
  • Calcium