Binding and assembly of actin filaments by plasma membranes from Dictyostelium discoideum
UMass Chan Affiliations
Department of Cell BiologyDocument Type
Journal ArticlePublication Date
1986-06-01Keywords
ActinsBinding Sites
Calcium-Binding Proteins
Cell Membrane
Cross-Linking Reagents
Cytoskeleton
Dictyostelium
Gelsolin
Intermediate Filaments
Kinetics
Microfilament Proteins
Phalloidine
Rhodamines
Staining and Labeling
Cell Biology
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
The binding of native, 125I-Bolton-Hunter-labeled actin to purified Dictyostelium discoideum plasma membranes was measured using a sedimentation assay. Binding was saturable only in the presence of the actin capping protein, gelsolin. In the presence of gelsolin, the amount of actin bound at saturation to three different membrane preparations was 80, 120, and 200 micrograms/mg of membrane protein. The respective concentrations of actin at half-saturation were 8, 12, and 18 micrograms/ml. The binding curves were sigmoidal, indicating positive cooperativity at low actin concentrations. This cooperativity appeared to be due to actin-actin associations during polymerization, since phalloidin converted the curve to a hyperbolic shape. In kinetic experiments, actin added as monomers bound to membranes at a rate of 0.6 microgram ml-1 min-1, while pre-polymerized actin bound at a rate of 3.0 micrograms ml-1 min-1. Even in the absence of phalloidin, actin bound to membranes at concentrations well below the normal critical concentration. This membrane-bound actin stained with rhodamine-phalloidin and was cross-linked by m-maleimidobenzoyl succinimide ester, a bifunctional cross-linker, into multimers with the same pattern observed for cross-linked F-actin. We conclude that D. discoideum plasma membranes bind actin specifically and saturably and that these membranes organize actin into filaments below the normal critical concentration for polymerization. This interaction probably occurs between multiple binding sites on the membrane and the side of the actin filament, and may be related to the clustering of membrane proteins.Source
J Cell Biol. 1986 Jun;102(6):2067-75. Link to article on publisher's website
DOI
10.1083/jcb.102.6.2067Permanent Link to this Item
http://hdl.handle.net/20.500.14038/50753PubMed ID
2423531Related Resources
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Publisher PDF posted as allowed by the publisher's terms of use policy at: http://www.rupress.org/terms After the Initial Publication Period, RUP will grant to the public the non-exclusive right to copy, distribute, or display the Article under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode, or updates thereof.Distribution License
http://creativecommons.org/licenses/by-nc-sa/4.0/ae974a485f413a2113503eed53cd6c53
10.1083/jcb.102.6.2067
Scopus Count
Except where otherwise noted, this item's license is described as Publisher PDF posted as allowed by the publisher's terms of use policy at: http://www.rupress.org/terms After the Initial Publication Period, RUP will grant to the public the non-exclusive right to copy, distribute, or display the Article under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode, or updates thereof.