July 29, 2010

The cytoskeleton of epithelial cells plays an important role in organization of the entire tissue. There are zonula adherens junctions that connect belts of actin within adjoining cells, and are important for epithelial sheet morphology and formation. This adhesion requires complex coordination of the actin cytoskeleton and its associated proteins. A recent paper has found that two isoforms of the same protein, myosin II, serve very different, but important, functions at these junctions. Image above shows epithelial cells with myosin IIA (green) and myosin IIB (magenta), and the merged image showing colocalization. The computer model image shows a 3D reconstruction of localization and intensity data, with color maps representing the intensity ranges of myosin IIA (min=blue, max=green) and myosin IIB (min=red, max=yellow).

Reference: Michael Smutny, Hayley L. Cox, Joanne M. Leerberg, Eva M. Kovacs, Mary Anne Conti, Charles Ferguson, Nicholas A. Hamilton, Robert G. Parton, Robert S. Adelstein and Alpha S. Yap. Reprinted by permission from Macmillan Publishers Ltd: Nature Cell Biology 12, 696 – 702, copyright 2010. Paper can be found here.

February 25, 2010

Networks of actin filaments can provide force within a cell to generate movement, but the mechanism of how this occurs isn’t completely understood. A group recently created a computer model to simulate and predict motility caused by actin polymerization, and tested new predictions experimentally. The figure above shows how an actin network uniformly coating a bead will break its symmetry to result in movement of the bead (top). The computer simulation (middle) and a 3D view of the simulation (bottom) are also shown.

Reference:

Mark J. Dayel, Orkun Akin, Mark Landeryou, Viviana Risca, Alex Mogilner, R. Dyche Mullins. Article found here.