title: Spatiotemporal relationships between the cell shape and the actomyosin cortex of periodically protruding cells.
abstract: We investigate the dynamics of cell shape and analyze the actin and myosin distributions of cells exhibiting cortical density traveling waves. These waves propagate by repeated cycles of cortical compression (folding) and dilation (unfolding) that lead to periodic protrusions (oscillations) of the cell boundary. The focus of our detailed analysis is the remarkable periodicity of this phenotype, in which both the overall shape transformation and distribution of actomyosin density are repeated from cycle to cycle even though the characteristics of the shape transformation vary significantly for different regions of the cell. We show, using correlation analysis, that during traveling wave propagation cortical actin and plasma membrane densities are tightly coupled at each point along the cell periphery. We also demonstrate that the major protrusion appears at the wave trailing edge just after the actin cortex density has reached a maximum. Making use of the extraordinary periodicity, we employ latrunculin to demonstrate that sequestering actin monomers can have two distinct effects: low latrunculin concentrations can trigger and enhance traveling waves but higher concentrations of this drug retard the waves. The fundamental mechanism underlying this periodically protruding phenotype, involving folding and unfolding of the cortex-membrane couple, is likely to hold important clues for diverse phenomena including cell division and amoeboid-type migration.
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland.
authors.forename: Meghan K
authors.initials: MK
authors.lastname: Driscoll
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland.|Institute for Physical Science and Technology, University of Maryland, College Park, Maryland.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Losert
authors.affiliation: Department of Cell Biology and Physiology, School of Medicine, UNC Chapel Hill, North Carolina.|Lineberger Comprehensive Cancer Center, School of Medicine, UNC Chapel Hill, North Carolina.
authors.forename: Ken
authors.initials: K
authors.lastname: Jacobson
authors.affiliation: Department of Cell Biology and Physiology, School of Medicine, UNC Chapel Hill, North Carolina.
authors.forename: Maryna
authors.initials: M
authors.lastname: Kapustina
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism*; D048430:Cell Shape; D013223:Statistics as Topic
chemical_list: D000205:Actomyosin
keywords: actin cortex; amoeboid-type migration; cell shape; correlation analysis; traveling wave