A membrane cytoskeleton from Dictyostelium discoideum. II. Integral proteins mediate the binding of plasma membranes to F-actin affinity beads
UMass Chan Affiliations
Department of Cell BiologyDocument Type
Journal ArticlePublication Date
1984-07-01Keywords
ActinsBinding, Competitive
Cell Membrane
Chromatography, Affinity
Cytoskeleton
Dictyostelium
Electrophoresis, Polyacrylamide Gel
Membrane Proteins
Microscopy, Electron
Molecular Weight
Cell Biology
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
In novel, low-speed sedimentation assays, highly purified, sonicated Dictyostelium discoideum plasma membrane fragments bind to F-actin beads (fluorescein-labeled F-actin on antifluorescein IgG-Sephacryl S-1000 beads). Binding was found to be (a) specific, since beads containing bound fluorescein-labeled ovalbumin or beads without bound fluorescein-labeled protein do not bind membranes, (b) saturable at approximately 0.6 microgram of membrane protein per microgram of bead-bound F-actin, (c) rapid with a t1/2 of 4-20 min, and (d) apparently of reasonable affinity since the off rate is too slow to be measured by present techniques. Using low-speed sedimentation assays, we found that sonicated plasma membrane fragments, after extraction with chaotropes, still bind F-actin beads. Heat-denatured membranes, proteolyzed membranes, and D. discoideum lipid vesicles did not bind F-actin beads. These results indicate that integral membrane proteins are responsible for the binding between sonicated membrane fragments and F-actin on beads. This finding agrees with the previous observation that integral proteins mediate interactions between D. discoideum plasma membranes and F-actin in solution (Luna, E.J., V. M. Fowler, J. Swanson, D. Branton, and D. L. Taylor, 1981, J. Cell Biol., 88:396-409). We conclude that low-speed sedimentation assays using F-actin beads are a reliable method for monitoring the associations between F-actin and membranes. Since these assays are relatively quantitative and require only micrograms of membranes and F-actin, they are a significant improvement over other existing techniques for exploring the biochemical details of F-actin-membrane interactions. Using F-actin beads as an affinity column for actin-binding proteins, we show that at least 12 integral polypeptides in D. discoideum plasma membranes bind to F-actin directly or indirectly. At least four of these polypeptides appear to span the membrane and are thus candidates for direct transmembrane links between the cytoskeleton and the cell surface.Source
J Cell Biol. 1984 Jul;99(1 Pt 1):58-70. Link to article on publisher's website
DOI
10.1083/jcb.99.1.58Permanent Link to this Item
http://hdl.handle.net/20.500.14038/50757PubMed ID
6539785Related Resources
Rights
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.99.1.58
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.