RT Journal Article
SR Electronic
T1 Delphilin: a Novel PDZ and Formin Homology Domain-Containing Protein that Synaptically Colocalizes and Interacts with Glutamate Receptor δ2 Subunit
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 803
OP 814
DO 10.1523/JNEUROSCI.22-03-00803.2002
VO 22
IS 3
A1 Yohei Miyagi
A1 Tetsuji Yamashita
A1 Masahiro Fukaya
A1 Tomoko Sonoda
A1 Toshiaki Okuno
A1 Kazuyuki Yamada
A1 Masahiko Watanabe
A1 Yoji Nagashima
A1 Ichiro Aoki
A1 Kenji Okuda
A1 Masayoshi Mishina
A1 Susumu Kawamoto
YR 2002
UL http://www.jneurosci.org/content/22/3/803.abstract
AB The glutamate receptor δ2 (GluRδ2) subunit is selectively expressed in cerebellar Purkinje cells and plays an important role in cerebellar long-term depression, motor learning, motor coordination, and synapse development. We identified a novel GluRδ2-interacting protein, named Delphilin, that contains a single PDZ domain and formin homology (FH) domains FH1 and FH2 plus coiled-coil structure. As far as we know, this is the first reported protein that contains both PDZ and FH domains. Yeast two-hybrid and surface plasmon resonance (SPR) analyses indicated that Delphilin interacts with the GluRδ2 C terminus via its PDZ domain. This was also supported by coimmunoprecipitation experiments using a heterologous expression system in mammalian cells. Yeast cell and SPR analyses also demonstrated the possibility that the FH1 proline-rich region of Delphilin interacts with profilin, an actin-binding protein, and with the Src homology 3 domain of neuronal Src protein tyrosine kinase. In situ hybridization demonstrated the highest expression of Delphilin mRNA in Purkinje cells. Delphilin polypeptide was highly enriched in the synaptosomal membrane fraction of the cerebellum and coimmunoprecipitated with the GluRδ2 subunit. The post-embedding immunogold technique demonstrated that Delphilin is selectively localized at the postsynaptic junction site of the parallel fiber–Purkinje cell synapse and colocalized with GluRδ2. Thus, Delphilin is a postsynaptic scaffolding protein at the parallel fiber–Purkinje cell synapse, where it may serve to link GluRδ2 with actin cytoskeleton and various signaling molecules.