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Research Database PMU-SQQUID

Specificity of dimer formation in tropomyosins: influence of alternatively spliced exons on homodimer and heterodimer assembly.
Gimona, M; Watakabe, A; Helfman, DM;
Proc Natl Acad Sci U S A. 1995; 92(21): 9776-9780.
Originalarbeiten (Zeitschrift)

PMU-Authors

Gimona Mario

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.


Useful keywords (using NLM MeSH Indexing)

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

Structure-Activity Relationship

Tropomyosin/genetics*

Tropomyosin/metabolism*


Find related publications in this database (Keywords)

PROTEIN-PROTEIN INTERACTION
PROTEIN SUBUNIT ASSOCIATION
COILED COIL
EPITOPE TAG