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An increase or a decrease in myosin II phosphorylation inhibits macrophage motility
A K Wilson1, G Gorgas, W D Claypool
1Department of Physiology, College of Medicine, University of Illinois, Chicago 60680.
The Journal of Cell Biology
|July 1, 1991
Summary
Myosin light chain kinase (MLCK) regulates cell motility by controlling MLC20 phosphorylation. Inhibiting or overactivating MLCK impairs macrophage migration, indicating phosphorylation must be tightly controlled.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Myosin II is crucial for cell motility.
- Myosin light chain kinase (MLCK) phosphorylates the myosin light chain 20 (MLC20) subunit.
- The role of MLC20 phosphorylation in regulating cell motility is not fully understood.
Purpose of the Study:
- To investigate the importance of MLC20 phosphorylation in regulating cell motility.
- To determine the effects of modulating MLCK activity on macrophage chemotaxis.
Main Methods:
- Macrophages were introduced with antibodies to MLCK (MK-Ab) or a constitutively active form of MLCK (MK-).
- Quantitative chemotaxis assays were used to measure cell motility.
- Intracellular MLC20 phosphorylation levels and myosin association with the cytoskeleton were analyzed.
Main Results:
- Macrophage chemotaxis was significantly diminished with MK-Ab, showing an inverse relationship between MK-Ab levels and cell migration.
- Constitutively active MK- also inversely correlated with cell migration, despite increasing MLC20 phosphorylation.
- MK-Ab decreased, while MK- increased, intracellular MLC20 phosphorylation and myosin-cytoskeleton association.
Conclusions:
- MLCK regulation is critical for mammalian cell motility.
- MLC20 phosphorylation must be maintained within narrow limits for effective cell migration.
- These findings highlight the precise control required for myosin-driven cellular processes.