title: Augmentation of alpha-actinin-induced gelation of actin by talin.
abstract: Interactions among the three major constituents of focal adhesions, talin, actin, and alpha-actinin, were studied. No evidence was obtained for the direct interaction between talin and alpha-actinin. Both talin and alpha-actinin increased the rate and extent of polymerization of actin, and their effects were additive. Whereas talin alone exhibited very little actin-gelating activity, it potentiated markedly the gelation in the presence of alpha-actinin and lowered the concentration of alpha-actinin necessary for the gel formation. Its gelation-potentiating activity on prepolymerized actin was much smaller than observed on G-actin. Treatment of talin with a cross-linking reagent, 1-ethyl-3[3-(dimethylamino)propyl]carbodiimide or dimethyl suberimidate, resulted in the formation of its oligomeric polypeptides. The complexes of talin and G-actin were also demonstrated with the cross-linking reagents and fluorescence-labeled actin. These results indicate that talin is able to cross-link some limited regions of actin filaments.
authors.affiliation: Department of Animal Science, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Muguruma
authors.forename: S
authors.initials: S
authors.lastname: Matsumura
authors.forename: T
authors.initials: T
authors.lastname: Fukazawa
mesh_terms: D000185:Actinin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004120:Dimethyl Suberimidate / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005782:Gels; D005895:Gizzard, Avian; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D011485:Protein Binding; D011817:Rabbits; D016608:Talin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000199:Actins; D003432:Cross-Linking Reagents; D005782:Gels; D046911:Macromolecular Substances; D016608:Talin; D000185:Actinin; D004120:Dimethyl Suberimidate