title: Cytoplasmic force gradient in migrating adhesive cells.
abstract: Amoeboid movement is believed to involve a pressure gradient along the cell length, with contractions in the posterior region driving cytoplasmic streaming forward. However, a parallel mechanism has yet to be demonstrated in migrating adhesive cells. To probe the distribution of intracellular forces, we microinjected high molecular weight linear polyacrylamide (PAA) as a passive force sensor into migrating NIH3T3 fibroblasts. Injected PAA appeared as amorphous aggregates that underwent shape change and directional movement in response to differential forces exerted by the surrounding environment. PAA injected into the posterior region moved toward the front, whereas PAA in the anterior region never moved to the posterior region. This preferential forward movement was observed only in migrating cells with a defined polarity. Disruption of myosin II activity by blebbistatin inhibited the forward translocation of PAA while cell migration persisted in a disorganized fashion. These results suggest a myosin II-dependent force gradient in migrating cells, possibly as a result of differential cortical contractions between the anterior and posterior regions. This gradient may be responsible for the forward transport of cellular components and for maintaining the directionality during cell migration.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Yu-Li
authors.initials: YL
authors.lastname: Wang
mesh_terms: D000180:Acrylic Resins / Q000494:pharmacology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D003593:Cytoplasm / Q000187:drug effects* / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D051379:Mice; D009044:Motor Cortex / Q000473:pathology / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D024462:Myosin Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D041681:NIH 3T3 Cells; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D006576:Heterocyclic Compounds, 4 or More Rings; D024462:Myosin Type II; D000099166:Polyacrylamides; C472645:blebbistatin