Knockdown of nuclear Ca2+/calmodulin-dependent protein kinase phosphatase causes developmental abnormalities in zebrafish

Takaki Nimura, Noriyuki Sueyoshi, Atsuhiko Ishida, Yukihiro Yoshimura, Makoto Ito, Hiroshi Tokumitsu, Yasushi Shigeri, Naohito Nozaki, Isamu Kameshita

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N) is an enzyme that dephosphorylates and concomitantly downregulates multifunctional Ca2+/calmodulin-dependent protein kinases (CaMKs) in vitro. However, the functional roles of this enzyme in vivo are not well understood. To investigate the biological significance of CaMKP-N during zebrafish embryogenesis, we cloned and characterized zebrafish CaMKP-N (zCaMKP-N). Based on the nucleotide sequences in the zebrafish whole genome shotgun database, we isolated a cDNA clone for zCaMKP-N, which encoded a protein of 633 amino acid residues. Transiently expressed full-length zCaMKP-N in mouse neuroblastoma, Neuro2a cells, was found to be localized in the nucleus. In contrast, the C-terminal truncated mutant lacking RKKRRLDVLPLRR (residues 575-587) had cytoplasmic staining, suggesting that the nuclear localization signal of zCaMKP-N exists in the C-terminal region. Ionomycin treatment of CaMKIV-transfected Neuro2a cells resulted in a marked increase in the phosphorylated form of CaMKIV. However, cotransfection with zCaMKP-N significantly decreased phospho-CaMKIV in ionomycin-stimulated cells. Whole mount in situ hybridization analysis of zebrafish embryos showed that zCaMKP-N is exclusively expressed in the head and neural tube regions. Gene knockdown of zCaMKP-N using morpholino-based antisense oligonucleotides induced significant morphological abnormalities in zebrafish embryos. A number of apoptotic cells were observed in brain and spinal cord of the abnormal embryos. These results suggest that zCaMKP-N plays a crucial role in the early development of zebrafish.

Original languageEnglish
Pages (from-to)205-216
Number of pages12
JournalArchives of Biochemistry and Biophysics
Volume457
Issue number2
DOIs
Publication statusPublished - Jan 15 2007
Externally publishedYes

Keywords

  • Apoptosis
  • CaM kinase
  • CaMKP
  • CaMKP-N
  • Phosphatase
  • Zebrafish

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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