Frequenin--a novel calcium-binding protein that modulates synaptic efficacy in the Drosophila nervous system

Neuron. 1993 Jul;11(1):15-28. doi: 10.1016/0896-6273(93)90267-u.


The T(X;Y)V7 rearrangement in Drosophila has originally been recognized as a Shaker-like mutant because of its behavioral and electrophysiological phenotype. The gene whose expression is altered by the V7 rearrangement has been characterized. It encodes a novel Ca(2+)-binding protein named frequenin, which is related to recoverin and visinin. In vitro, the frequenin protein functions like recoverin as a Ca(2+)-sensitive guanylyl cyclase activator. Anti-frequenin antibodies stain the central and peripheral nervous system in Drosophila embryos and in larval and adult tissue sections. Frequenin appears to be particularly enriched in synapses, such as the motor nerve endings at neuromuscular junctions. Neuromuscular junctions of transgenic flies, which overexpress frequenin upon heat shock, exhibit an extraordinarily enhanced, frequency-dependent facilitation of neurotransmitter release, with properties identical to those observed in V7 junctions. We propose that frequenin represents a new element for the Ca(2+)-dependent modulation of synaptic efficacy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism
  • Calcium-Binding Proteins / physiology*
  • Drosophila / physiology*
  • Drosophila Proteins*
  • Gene Rearrangement
  • Guanylate Cyclase / metabolism
  • Molecular Probes / genetics
  • Molecular Sequence Data
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Nerve Tissue Proteins / physiology*
  • Nervous System / metabolism
  • Nervous System Physiological Phenomena*
  • Neuromuscular Junction / physiology
  • Neurotransmitter Agents / metabolism
  • Synapses / physiology*
  • Synaptic Transmission / physiology


  • Calcium-Binding Proteins
  • Drosophila Proteins
  • Frq protein, Drosophila
  • Molecular Probes
  • Nerve Tissue Proteins
  • Neurotransmitter Agents
  • Guanylate Cyclase

Associated data

  • GENBANK/L08064