title: Specific interaction of vinculin with alpha-actinin.
abstract: Vinculin and alpha-actinin are cytoskeletal proteins present at focal contacts of the ventral surface of cultured fibroblasts. We labelled alpha-actinin with an acceptor fluorophore and vinculin with a donor. A mixture of vinculin and alpha-actinin showed a 28% quench, due to energy transfer, suggesting an interaction. Quench of vinculin was dependent on the concentration of alpha-actinin; Scatchard analysis gives a dissociation constant in the microM range. Quench was inhibited by excess unlabelled alpha-actinin, and by reaction of the acceptor protein with p-chloromercuribenzoate. We found that vinculin had a slightly greater elution volume in a gel filtration column equilibrated with alpha-actinin, indicating a higher effective Stokes radius due to the interaction of the two proteins.
mesh_terms: D000185:Actinin / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D005895:Gizzard, Avian / Q000032:analysis; D009124:Muscle Proteins / Q000378:metabolism*; D009282:Naphthalenesulfonates; D013050:Spectrometry, Fluorescence; D016596:Vinculin
chemical_list: D009124:Muscle Proteins; D009282:Naphthalenesulfonates; D000185:Actinin; D016596:Vinculin; C006421:1,5-I-AEDANS