Talin influences the dynamics of the myosin VII-membrane interaction.
Myosin VII (M7) and talin are ancient and ubiquitous actin-binding proteins with conserved roles in adhesion. Talin serves to link membrane receptors to the underlying actin cytoskeleton and forms a complex with M7 in Dictyostelium. The levels of talinA are tightly linked to M7 levels in Dictyostelium. Cells lacking M7 exhibit an 80% decrease in steady-state levels of talinA, whereas increased levels of M7 result in concomitant increases in total talinA. In contrast, changes in talinA levels do not affect M7 levels. Immunoprecipitation reveals that talinA and M7 are associated with each other in membrane fractions. Fluorescence recovery after photobleaching experiments on green fluorescent protein (GFP)-M7 cells expressing different levels of the M7 and talinA show that changes in the overall amounts of these two proteins influences the dynamics of membrane-associated M7. The recovery of GFP-M7 on the membrane is faster in cells lacking talinA and limited in the presence of excess amounts of talinA and M7. These results establish that M7 stabilizes talinA in the cytosol and, in return, talinA regulates the residence time of M7 at the plasma membrane, suggesting that these two proteins are both part of the same dynamic adhesion complex on the plasma membrane.
Department of Genetics, Cell Biology, and Development and Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
Shawn A
SA
Galdeen
Stephen
S
Stephens
David D
DD
Thomas
Margaret A
MA
Titus
D000818:Animals; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism*; D004023:Dictyostelium / Q000378:metabolism*; D047468:Immunoprecipitation; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009218:Myosins / Q000737:chemistry / Q000378:metabolism*; D010641:Phenotype; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016608:Talin / Q000172:deficiency / Q000378:metabolism*; D013816:Thermodynamics
D011993:Recombinant Fusion Proteins; D016608:Talin; D009218:Myosins