N-cadherin prodomain cleavage regulates synapse formation in vivo

Dev Neurobiol. 2009 Jul;69(8):518-29. doi: 10.1002/dneu.20718.

Abstract

Cadherins are initially synthesized bearing a prodomain that is thought to limit adhesion during early stages of biosynthesis. Functional cadherins lack this prodomain, raising the intriguing possibility that cells may utilize prodomain cleavage as a means to temporally or spatially regulate adhesion after delivery of cadherin to the cell surface. In support of this idea, immunostaining for the prodomain of zebrafish N-cadherin revealed enriched labeling at neuronal surfaces at the soma and along axonal processes. To determine whether post-translational cleavage of the prodomain affects synapse formation, we imaged Rohon-Beard cells in zebrafish embryos expressing GFP-tagged wild-type N-cadherin (NCAD-GFP) or a GFP-tagged N-cadherin mutant expressing an uncleavable prodomain (PRON-GFP) rendering it nonadhesive. NCAD-GFP accumulated at synaptic microdomains in a developmentally regulated manner, and its overexpression transiently accelerated synapse formation. PRON-GFP was much more diffusely distributed along the axon and its overexpression delayed synapse formation. Our results support the notion that N-cadherin serves to stabilize pre- to postsynaptic contacts early in synapse development and suggests that regulated cleavage of the N-cadherin prodomain may be a mechanism by which the kinetics of synaptogenesis are regulated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism
  • Axons / ultrastructure
  • Brain / cytology
  • Brain / embryology*
  • Brain / metabolism*
  • Cadherins / chemistry
  • Cadherins / genetics
  • Cadherins / metabolism*
  • Cell Differentiation / physiology
  • Cells, Cultured
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Kinetics
  • Mutation / genetics
  • Neural Pathways / embryology
  • Neural Pathways / metabolism
  • Neural Pathways / ultrastructure
  • Protein Structure, Tertiary / physiology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Synapses / metabolism*
  • Synapses / ultrastructure
  • Synaptic Membranes / metabolism
  • Synaptic Membranes / ultrastructure
  • Zebrafish / anatomy & histology
  • Zebrafish / embryology*
  • Zebrafish / metabolism*
  • Zebrafish Proteins / chemistry
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism*

Substances

  • Cadherins
  • N-cadherin, zebrafish
  • Recombinant Fusion Proteins
  • Zebrafish Proteins
  • Green Fluorescent Proteins