Abstract
Myosin II regulatory light chain (RLC) phosphorylation by Ca 2+/calmodulin (CaM)-dependent myosin light chain kinase (MLCK) is implicated in many cellular actin cytoskeletal functions. We examined MLCK activation quantitatively with a fluorescent biosensor MLCK where Ca 2+-dependent increases in kinase activity were coincident with decreases in fluorescence resonance energy transfer (FRET) in vitro. In cells stably transfected with CaM sensor MLCK, increasing [Ca2+] i increased MLCK activation and RLC phosphorylation coincidently. There was no evidence for CaM binding but not activating MLCK at low [Ca 2+]i. At saturating [Ca2+]i MLCK was not fully activated probably due to limited availability of cellular Ca 2+/CaM.
Original language | English (US) |
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Pages (from-to) | 121-124 |
Number of pages | 4 |
Journal | FEBS Letters |
Volume | 557 |
Issue number | 1-3 |
DOIs | |
State | Published - Jan 16 2004 |
Keywords
- Calcium
- Calmodulin
- Fluorescence resonance energy transfer
- Myosin light chain kinase
- Phosphorylation
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Biochemistry
- Molecular Biology
- Genetics
- Cell Biology