PIP3-Phldb2 is crucial for LTP regulating synaptic NMDA and AMPA receptor density and PSD95 turnover

Sci Rep. 2019 Mar 13;9(1):4305. doi: 10.1038/s41598-019-40838-6.

Abstract

The essential involvement of phosphoinositides in synaptic plasticity is well-established, but incomplete knowledge of the downstream molecular entities prevents us from understanding their signalling cascades completely. Here, we determined that Phldb2, of which pleckstrin-homology domain is highly sensitive to PIP3, functions as a phosphoinositide-signalling mediator for synaptic plasticity. BDNF application caused Phldb2 recruitment toward postsynaptic membrane in dendritic spines, whereas PI3K inhibition resulted in its reduced accumulation. Phldb2 bound to postsynaptic scaffolding molecule PSD-95 and was crucial for localization and turnover of PSD-95 in the spine. Phldb2 also bound to GluA1 and GluA2. Phldb2 was indispensable for the interaction between NMDA receptors and CaMKII, and the synaptic density of AMPA receptors. Therefore, PIP3-responsive Phldb2 is pivotal for induction and maintenance of LTP. Memory formation was impaired in our Phldb2-/- mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
  • Carrier Proteins / metabolism*
  • Disks Large Homolog 4 Protein / metabolism*
  • Long-Term Potentiation / physiology*
  • Membrane Proteins / metabolism*
  • Memory
  • Mice
  • Neuronal Plasticity
  • Phosphatidylinositol Phosphates / metabolism*
  • Protein Binding / physiology
  • Receptors, AMPA / metabolism*
  • Receptors, N-Methyl-D-Aspartate / metabolism*

Substances

  • Carrier Proteins
  • Disks Large Homolog 4 Protein
  • Membrane Proteins
  • Phldb2 protein, mouse
  • Phosphatidylinositol Phosphates
  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • phosphatidylinositol 3-phosphate
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2