Specificity of dimer formation in tropomyosins: influence of alternatively spliced exons on homodimer and heterodimer assembly

Gimona, M., Watakabe, A., Helfman, D. M. (October 1995) Specificity of dimer formation in tropomyosins: influence of alternatively spliced exons on homodimer and heterodimer assembly. Proc Natl Acad Sci U S A, 92 (21). pp. 9776-80. ISSN 0027-8424 (Print)

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URL: http://www.ncbi.nlm.nih.gov/pubmed/7568216

Abstract

Tropomyosins consist of nearly 100% alpha-helix and assemble into parallel and in-register coiled-coil dimers. In vitro it has been established that nonmuscle as well as native muscle tropomyosins can form homodimers. However, a mixture of muscle alpha and beta tropomyosin subunits results in the formation of the thermodynamically more stable alpha/beta heterodimer. Although the assembly preference of the muscle tropomyosin heterodimer can be understood thermodynamically, the presence of multiple tropomyosin isoforms expressed in nonmuscle cells points toward a more complex principle for determining dimer formation. We have investigated the dimerization of rat tropomyosins in living cells by the use of epitope tagging with a 16-aa sequence of the influenza hemagglutinin. Employing transfection and immunoprecipitation techniques, we have analyzed the dimers formed by muscle and nonmuscle tropomyosins in rat fibroblasts. We demonstrate that the information for homo- versus heterodimerization is contained within the tropomyosin molecule itself and that the information for the selectivity is conferred by the alternatively spliced exons. These results have important implications for models of the regulation of cytoskeletal dynamics.

Item Type: Paper
Uncontrolled Keywords: Alternative Splicing Amino Acid Sequence Animals Base Sequence Cytoskeleton/metabolism Epitopes/genetics Fibroblasts/cytology Fluorescent Antibody Technique Molecular Sequence Data Muscle, Skeletal/cytology Muscle, Smooth/cytology Protein Binding Protein Conformation Rats Recombinant Proteins/metabolism Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Structure-Activity Relationship Tropomyosin/ genetics/ metabolism
Subjects: bioinformatics > genomics and proteomics > design > amino acid design
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > Alternative Splicing
organism description > animal
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > fibroblasts
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > fibroblasts
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > fibroblasts

bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
organism description > animal > mammal > rodent > rat
organism description > animal > mammal > rodent > rat

organs, tissues, organelles, cell types and functions > tissues types and functions > smooth muscle
CSHL Authors:
Communities: CSHL labs > Helfman lab
Depositing User: Jessica Koos
Date: 10 October 1995
Date Deposited: 15 Aug 2014 19:30
Last Modified: 09 Nov 2017 19:26
PMCID: PMC40885
Related URLs:
URI: http://repository.cshl.edu/id/eprint/30594

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