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Myosin I phosphorylation is increased by chemotactic stimulation
N R Gliksman1, G Santoyo, K D Novak
1Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
The Journal of Biological Chemistry
|November 21, 2000
Summary
Chemotactic stimulation increases the phosphorylation of Dictyostelium myosin I (myoB) in vivo. This phosphorylation enhances myoB activity, contributing to pseudopod extension during directed cell migration.
Area of Science:
- Cell biology
- Biochemistry
- Molecular biology
Background:
- Directed cell migration is crucial for cellular functions and relies on cytoskeletal rearrangements.
- Amoeboid myosin I proteins are essential for pseudopod formation during cell movement.
- Myosin I activity is regulated by phosphorylation of its heavy chain.
Purpose of the Study:
- To investigate the effect of chemotactic stimulation on the in vivo phosphorylation of Dictyostelium myosin I, specifically myoB.
- To determine if myoB heavy chain phosphorylation is altered by chemoattractant stimulation.
Main Methods:
- Studying Dictyostelium discoideum cells.
- Utilizing chemotactic stimulation with cAMP.
- Measuring in vivo phosphorylation levels of the myoB heavy chain on serine 322.
Main Results:
- The myoB heavy chain is phosphorylated in vivo at serine 322 in chemotactically competent cells.
- Chemotactic stimulation with cAMP significantly increases myoB phosphorylation.
- A peak 3-fold increase in myoB phosphorylation occurs at 60 seconds post-stimulation, coinciding with pseudopod extension.
Conclusions:
- Chemotactic stimulation elevates myoB activity through heavy chain phosphorylation.
- Increased myoB activity contributes to the pseudopod extension observed before cell polarization and directed motility.
- This phosphorylation mechanism is a key regulator of directed cell migration in Dictyostelium.