• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Cast: a novel protein of the cytomatrix at the active zone of synapses that forms a ternary complex with RIM1 and munc13-1.

The cytomatrix at the active zone (CAZ) has been implicated in defining the site of Ca2+-dependent exocytosis of neurotransmitter. We have identified here a novel CAZ protein of approximately 120 kD from rat brain and named it CAST (CAZ-associated structural protein). CAST had no transmembrane segment, but had four coiled-coil domains and a putative COOH-terminal consensus motif for binding to PDZ domains. CAST was localized at the CAZ of conventional synapses of mouse brain. CAST bound directly RIM1 and indirectly Munc13-1, presumably through RIM1, forming a ternary complex. RIM1 and Munc13-1 are CAZ proteins implicated in Ca2+-dependent exocytosis of neurotansmitters. Bassoon, another CAZ protein, was also associated with this ternary complex. These results suggest that a network of protein-protein interactions among the CAZ proteins exists at the CAZ. At the early stages of synapse formation, CAST was expressed and partly colocalized with bassoon in the axon shaft and the growth cone. The vesicles immunoisolated by antibassoon antibody-coupled beads contained not only bassoon but also CAST and RIM1. These results suggest that these CAZ proteins are at least partly transported on the same vesicles during synapse formation.

Pubmed ID: 12163476

Authors

  • Ohtsuka T
  • Takao-Rikitsu E
  • Inoue E
  • Inoue M
  • Takeuchi M
  • Matsubara K
  • Deguchi-Tawarada M
  • Satoh K
  • Morimoto K
  • Nakanishi H
  • Takai Y

Journal

The Journal of cell biology

Publication Data

August 5, 2002

Associated Grants

None

Mesh Terms

  • Aging
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Brain
  • Cell Compartmentation
  • Cell Differentiation
  • Cells, Cultured
  • Cloning, Molecular
  • Cytoplasm
  • DNA, Complementary
  • GTP-Binding Proteins
  • Gene Expression Regulation, Developmental
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Macromolecular Substances
  • Membrane Proteins
  • Mice
  • Nerve Tissue Proteins
  • Neurons
  • Protein Binding
  • Rats
  • Synaptic Membranes
  • Synaptic Transmission
  • Synaptophysin