Abstract
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 language | English |
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Pages (from-to) | 57-63 |
Number of pages | 7 |
Journal | FEBS Letters |
Volume | 550 |
Issue number | 1-3 |
DOIs | |
Publication status | Published - Aug 28 2003 |
Externally published | Yes |
Keywords
- Ca
- CaM-K kinase
- CaM-kinase cascade
- CaM-kinaseδ
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Biochemistry
- Molecular Biology
- Genetics
- Cell Biology