Abstract
Short and long myosin light chain kinases (MLCKs) are Ca2+/calmodulin-dependent enzymes that phosphorylate the regulatory light chain of myosin II in thick filaments but bind with high affinity to actin thin filaments. Three repeats of a motif made up of the sequence DFRXXL at the N terminus of short MLCK are necessary for actin binding (Smith, L., Su, X., Lin, P., Zhi, G., and Stull, J. T. (1999) J. Biol. Chem. 274, 29433-29438). The long MLCK has two additional DFRXXL motifs and six Ig-like modules in an N-terminal extension, which may confer unique binding properties for cellular localization. Two peptides containing either five or three DFRXXL motifs bound to F-actin and smooth muscle myofilaments with maximal binding stoichiometries consistent with each motif binding to an actin monomer in the filaments. Both peptides cross-linked F-actin and bound to stress fibers in cells. Long MLCK with an internal deletion of the five DFRXXL motifs and the unique NH2-terminal fragment containing six Ig-like motifs showed weak binding. Cell fractionation and extractions with MgCl2 indicate that the long MLCK has a greater affinity for actin-containing filaments than short MLCK in vitro and in vivo. Whereas DFRXXL motifs are necessary and sufficient for short MLCK binding to actin-containing filaments, the DFRXXL motifs and the N-terminal extension of long MLCK confer high affinity binding to stress fibers in cells.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 35597-35604 |
| Number of pages | 8 |
| Journal | Journal of Biological Chemistry |
| Volume | 277 |
| Issue number | 38 |
| DOIs | |
| State | Published - Sep 20 2002 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Properties of long myosin light chain kinase binding to F-actin in vitro and in vivo. / Smith, Lula; Parizi-Robinson, Mojgan; Zhu, Min Sheng; Zhi, Gang; Fukui, Ryosuke; Kamm, Kristine E.; Stull, James T.
In: Journal of Biological Chemistry, Vol. 277, No. 38, 20.09.2002, p. 35597-35604.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Properties of long myosin light chain kinase binding to F-actin in vitro and in vivo
AU - Smith, Lula
AU - Parizi-Robinson, Mojgan
AU - Zhu, Min Sheng
AU - Zhi, Gang
AU - Fukui, Ryosuke
AU - Kamm, Kristine E.
AU - Stull, James T.
PY - 2002/9/20
Y1 - 2002/9/20
N2 - Short and long myosin light chain kinases (MLCKs) are Ca2+/calmodulin-dependent enzymes that phosphorylate the regulatory light chain of myosin II in thick filaments but bind with high affinity to actin thin filaments. Three repeats of a motif made up of the sequence DFRXXL at the N terminus of short MLCK are necessary for actin binding (Smith, L., Su, X., Lin, P., Zhi, G., and Stull, J. T. (1999) J. Biol. Chem. 274, 29433-29438). The long MLCK has two additional DFRXXL motifs and six Ig-like modules in an N-terminal extension, which may confer unique binding properties for cellular localization. Two peptides containing either five or three DFRXXL motifs bound to F-actin and smooth muscle myofilaments with maximal binding stoichiometries consistent with each motif binding to an actin monomer in the filaments. Both peptides cross-linked F-actin and bound to stress fibers in cells. Long MLCK with an internal deletion of the five DFRXXL motifs and the unique NH2-terminal fragment containing six Ig-like motifs showed weak binding. Cell fractionation and extractions with MgCl2 indicate that the long MLCK has a greater affinity for actin-containing filaments than short MLCK in vitro and in vivo. Whereas DFRXXL motifs are necessary and sufficient for short MLCK binding to actin-containing filaments, the DFRXXL motifs and the N-terminal extension of long MLCK confer high affinity binding to stress fibers in cells.
AB - Short and long myosin light chain kinases (MLCKs) are Ca2+/calmodulin-dependent enzymes that phosphorylate the regulatory light chain of myosin II in thick filaments but bind with high affinity to actin thin filaments. Three repeats of a motif made up of the sequence DFRXXL at the N terminus of short MLCK are necessary for actin binding (Smith, L., Su, X., Lin, P., Zhi, G., and Stull, J. T. (1999) J. Biol. Chem. 274, 29433-29438). The long MLCK has two additional DFRXXL motifs and six Ig-like modules in an N-terminal extension, which may confer unique binding properties for cellular localization. Two peptides containing either five or three DFRXXL motifs bound to F-actin and smooth muscle myofilaments with maximal binding stoichiometries consistent with each motif binding to an actin monomer in the filaments. Both peptides cross-linked F-actin and bound to stress fibers in cells. Long MLCK with an internal deletion of the five DFRXXL motifs and the unique NH2-terminal fragment containing six Ig-like motifs showed weak binding. Cell fractionation and extractions with MgCl2 indicate that the long MLCK has a greater affinity for actin-containing filaments than short MLCK in vitro and in vivo. Whereas DFRXXL motifs are necessary and sufficient for short MLCK binding to actin-containing filaments, the DFRXXL motifs and the N-terminal extension of long MLCK confer high affinity binding to stress fibers in cells.
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U2 - 10.1074/jbc.M206483200
DO - 10.1074/jbc.M206483200
M3 - Article
VL - 277
SP - 35597
EP - 35604
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 38
ER -