title: Cell substratum adhesion during early development of Dictyostelium discoideum.
abstract: Vegetative and developed amoebae of Dictyostelium discoideum gain traction and move rapidly on a wide range of substrata without forming focal adhesions. We used two independent assays to quantify cell-substrate adhesion in mutants and in wild-type cells as a function of development. Using a microfluidic device that generates a range of hydrodynamic shear stress, we found that substratum adhesion decreases at least 10 fold during the first 6 hr of development of wild type cells. This result was confirmed using a single-cell assay in which cells were attached to the cantilever of an atomic force probe and allowed to adhere to untreated glass surfaces before being retracted. Both of these assays showed that the decrease in substratum adhesion was dependent on the cAMP receptor CAR1 which triggers development. Vegetative cells missing talin as the result of a mutation in talA exhibited slightly reduced adhesive properties compared to vegetative wild-type cells. In sharp contrast to wild-type cells, however, these talA mutant cells did not show further reduction of adhesion during development such that after 5 hr of development they were significantly more adhesive than developed wild type cells. In addition, both assays showed that substrate adhesion was reduced in 0 hr cells when the actin cytoskeleton was disrupted by latrunculin. Consistent with previous observations, substrate adhesion was also reduced in 0 hr cells lacking the membrane proteins SadA or SibA as the result of mutations in sadA or sibA. However, there was no difference in the adhesion properties between wild type AX3 cells and these mutant cells after 6 hr of development, suggesting that neither SibA nor SadA play an essential role in substratum adhesion during aggregation. Our results provide a quantitative framework for further studies of cell substratum adhesion in Dictyostelium.
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), Laboratory for Fluid Dynamics, Pattern Formation and Biocomplexity, Goettingen, Germany; Center for Theoretical Biological Physics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Marco
authors.initials: M
authors.lastname: Tarantola
authors.affiliation: Center for Theoretical Biological Physics, University of California San Diego, La Jolla, California, United States of America; Department of Physics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Albert
authors.initials: A
authors.lastname: Bae
authors.affiliation: Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Danny
authors.initials: D
authors.lastname: Fuller
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), Laboratory for Fluid Dynamics, Pattern Formation and Biocomplexity, Goettingen, Germany; Institute of Nonlinear Dynamics, Georg-August University, Goettingen, Germany; Laboratory of Atomic and Solid-state Physics, Cornell University, Ithaca, New York, United States of America.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Bodenschatz
authors.affiliation: Center for Theoretical Biological Physics, University of California San Diego, La Jolla, California, United States of America; Department of Physics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Wouter-Jan
authors.initials: WJ
authors.lastname: Rappel
authors.affiliation: Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America.
authors.forename: William F
authors.initials: WF
authors.lastname: Loomis
mesh_terms: D002448:Cell Adhesion; D002465:Cell Movement; D004023:Dictyostelium / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D022001:Focal Adhesions / Q000378:metabolism; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D018625:Microscopy, Atomic Force; D009154:Mutation; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D059010:Single-Cell Analysis / Q000379:methods; D016608:Talin / Q000235:genetics / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D016608:Talin