Synaptic targeting of PSD-Zip45 (Homer 1c) and its involvement in the synaptic accumulation of F-actin

Shinichi Usui, Daijiro Konno, Kei Hori, Hisato Maruoka, Shigeo Okabe, Takashi Fujikado, Yasuo Tano, Kenji Sobue

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39 Citations (Scopus)


PSD-Zip45/Homer1c, which contains an enabled/VASP homology 1 (EVH1) domain and leucine zipper motifs, is a postsynaptic density (PSD) scaffold protein that interacts with metabotropic glutamate receptors and the shank family. We studied the molecular mechanism underlying the synaptic targeting of PSD-Zip45 in cultured hippocampal neurons. The EVH1 domain and the extreme C-terminal leucine zipper motif were molecular determinants for its synaptic targeting. The overexpression of the mutant of the EVH1 domain or deletion of the extreme C-terminal leucine zipper motif markedly suppressed the synaptic localization of endogenous shank but not PSD-95 or GKAP. In contrast, an overexpressed GKAP mutant lacking shank binding activity had no effect on the synaptic localization of shank. Actin depolymerization by latrunculin A reduced the synaptic localization of PSD-Zip45, shank, and F-actin but not of PSD-95 or GKAP. Overexpression of PSD-Zip45 enhanced the accumulation of synaptic F-actin. Additionally, overexpression of PSD-Zip45 and an isoform of shank induced synaptic enlargement in association with the further accumulation of synaptic F-actin. The EVH1 domain and extreme C-terminal leucine zipper motif of PSD-Zip45 were also critical for these events. Thus, these data suggest that the PSD-Zip45-shank and PSD-95-GKAP complexes form different synaptic compartments, and PSD-Zip45 alone or PSD-Zip45-shank is involved in the synaptic accumulation of F-actin.

Original languageEnglish
Pages (from-to)10619-10628
Number of pages10
JournalJournal of Biological Chemistry
Issue number12
Publication statusPublished - Mar 21 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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