A role for myosin VII in dynamic cell adhesion.
BACKGROUND
The initial stages of phagocytosis and cell motility resemble each other. The extension of a pseudopod at the leading edge of a migratory cell and the formation of a phagocytic cup are actin dependent, and each rely on the plasma membrane adhering to a surface during dynamic extension.


RESULTS
A myosin VII null mutant exhibited a drastic loss of adhesion to particles, consistent with the extent of an observed decrease in particle uptake. Additionally, cell-cell adhesion and the adhesion of the leading edge to the substratum during cell migration were defective in the myosin VII null cells. GFP-myosin VII rescued the phagocytosis defect of the null mutant and was distributed in the cytosol and recruited to the cortical cytoskeleton, where it appeared to be enriched at the tips of filopods. It was also localized to phagocytic cups, but only during the initial stages of particle engulfment. During migration, GFP-myosin VII is found at the leading edge of the cell.


CONCLUSIONS
Myosin VII plays an important role in mediating the initial binding of cells to substrata, a novel role for an unconventional myosin.
Department of Genetics, Cell Biology, and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA.
R I
RI
Tuxworth
I
I
Weber
D
D
Wessels
G C
GC
Addicks
D R
DR
Soll
G
G
Gerisch
M A
MA
Titus
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D004023:Dictyostelium / Q000502:physiology; D016296:Mutagenesis; D009218:Myosins / Q000235:genetics / Q000502:physiology*; D010587:Phagocytosis / Q000502:physiology; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology
D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C407348:myosin VII protein, Dictyostelium discoideum; D009218:Myosins