NGPF2 triggers synaptic scaling up through ALK-LIMK-cofilin-mediated mechanisms

Cell Rep. 2021 Aug 17;36(7):109515. doi: 10.1016/j.celrep.2021.109515.

Abstract

Synaptic scaling is an extensively studied form of homeostatic plasticity critically involved in various brain functions. Although it is accepted that synaptic scaling is expressed through the postsynaptic accumulation of AMPA receptors (AMPARs), the induction mechanism remains elusive. In this study, we show that TTX treatment induces rapid but transient release of the neurite growth-promoting factor 2 (NGPF2), and this release is necessary and sufficient for TTX-induced scaling up. In addition, we show that inhibition of the anaplastic lymphoma kinase (ALK)-LIMK-cofilin signaling pathway blocks TTX- and NGPF2-induced synaptic scaling up. Furthermore, we show that TTX-induced release of NGPF2 is protein synthesis dependent and requires fragile X mental retardation protein 1 (FMRP1). These results indicate that activity blockade induces NGPF2 synthesis and release to trigger synaptic scaling up through LIMK-cofilin-dependent actin reorganization, spine enlargement, and stabilization of AMPARs at the synapse.

Keywords: AMPA receptor; LIM-kinase; anaplastic lymphoma kinase; cofilin; fragile X mental retardation protein 1; neurite growth promoting factor 2; synaptic scaling up.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Depolymerizing Factors / metabolism
  • Anaplastic Lymphoma Kinase
  • Animals
  • CHO Cells
  • Cricetulus
  • Dendritic Spines / drug effects
  • Dendritic Spines / metabolism
  • Excitatory Postsynaptic Potentials / drug effects
  • Fragile X Mental Retardation Protein / metabolism
  • Lim Kinases / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Nerve Tissue Proteins* / metabolism
  • Protein Biosynthesis
  • Receptors, AMPA / metabolism
  • Signal Transduction
  • Synapses / drug effects
  • Synapses / metabolism
  • Tetrodotoxin / pharmacology

Substances

  • Actin Depolymerizing Factors
  • Anaplastic Lymphoma Kinase
  • Fragile X Mental Retardation Protein
  • Lim Kinases
  • Limk1 protein, mouse
  • Nerve Tissue Proteins
  • Receptors, AMPA
  • Tetrodotoxin
  • Mdk protein, mouse