Identification and characterization of novel components of a Ca 2+/calmodulin-dependent protein kinase cascade in HeLa cells

Yumi Ishikawa, Hiroshi Tokumitsu, Hiroyuki Inuzuka, Maki Murata-Hori, Hiroshi Hosoya, Ryoji Kobayashi

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


In this report, we cloned a novel calmodulin-kinase (CaM-KIδ) from HeLa cells and characterized its activation mechanism. CaM-KIδ exhibits Ca2+/CaM-dependent activity that is enhanced (∼30-fold) in vitro by phosphorylation of its Thr180 by CaM-K kinase (CaM-KK)α, consistent with detection of CaM-KIδ-activating activity in HeLa cells. We also identified a novel CaM-KKβ isoform (CaM-KKβ-3) in HeLa cells whose activity was highly Ca2+/CaM-independent. Transiently expressed CaM-KIδ exhibited enhanced protein kinase activity in HeLa cells without ionomycin stimulation. This sustained activation of CaM-KIδ was completely abolished by Thr180Ala mutation and inhibited by CaM-KK inhibitor, STO-609, indicating a functional CaM-KK/CaM-KIδ cascade in HeLa cells.

Original languageEnglish
Pages (from-to)57-63
Number of pages7
JournalFEBS Letters
Issue number1-3
Publication statusPublished - Aug 28 2003
Externally publishedYes


  • Ca
  • CaM-K kinase
  • CaM-kinase cascade
  • CaM-kinaseδ

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


Dive into the research topics of 'Identification and characterization of novel components of a Ca <sup>2+</sup>/calmodulin-dependent protein kinase cascade in HeLa cells'. Together they form a unique fingerprint.

Cite this