title: An alpha-actinin isoform which may cross-link intermediate filaments and microfilaments.
abstract: The G.3.5 antigen (named for the monoclonal antibody which recognizes it) has been characterized as an intermediate filament-associated protein found in a variety of tissue types, including human and rat astrocytes, rat skeletal and cardiac myocytes, fibroblasts, rat hepatocytes, and chicken and fish retinal tissues. Sequencing of proteolytic fragments indicated a high degree of similarity to alpha-actinin. Comparison of the G.3.5 antigen to alpha-actinin revealed that alpha-actinin and the G.3.5 antigen migrated similarly in reducing and non-reducing environments and had similar molecular masses (approximately 100,000). Overlay-immunoblotting assays indicated that the G.3.5 antigen and alpha-actinin could bind filamentous actin and desmin simultaneously. In contrast, immunocytochemistry indicated the G.3.5 antigen and alpha-actinin were immunologically distinct in tissue sections. The results of this study suggest that the G.3.5 antigen is an isoform of alpha-actinin which may serve to cross-link intermediate filaments to microfilaments, and that other isoforms of alpha-actinin may also share this property.
authors.affiliation: Department of Biology, Southwest Texas State University, San Marcos 78666, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Bolanos
authors.forename: D O
authors.initials: DO
authors.lastname: Zamora
authors.forename: D M
authors.initials: DM
authors.lastname: García
authors.forename: J R
authors.initials: JR
authors.lastname: Koke
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D000185:Actinin / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D002417:Cattle; D002645:Chickens; D006801:Humans; D017403:In Situ Hybridization; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D007382:Intermediate Filaments / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009124:Muscle Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000737:chemistry; D009130:Muscle, Smooth / Q000737:chemistry; D020033:Protein Isoforms / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D007381:Intermediate Filament Proteins; D009124:Muscle Proteins; D020033:Protein Isoforms; D000185:Actinin