Human skeletal muscle-specific alpha-actinin-2 and -3 isoforms form homodimers and heterodimers in vitro and in vivo.
Alpha-actinins belong to a family of actin-binding and crosslinking proteins and are expressed in many different cell types. Multiple isoforms of alpha-actinin are found in humans and are encoded by at least four distinct genes. Human skeletal muscle contains two sarcomeric isoforms, alpha-actinin-2 and -3. Previous studies have shown that ... the alpha-actinins function as anti-parallel homodimers but the question of heterodimer formation between two different isoforms expressed in the same cell type has not been explored. To address this issue, we expressed both alpha-actinin-2 and -3 in vitro and were able to detect their interaction by both blot overlay and co-immunoprecipitation methods. We were also able to demonstrate the presence of heterodimers in vivo in human skeletal muscle and in COS-1 cells transiently transfected with both isoforms. Our results clearly demonstrate the potential for alpha-actinin isoforms to form heterodimers which might have unique functional characteristics.
Mesh Terms:
Actinin, Amino Acid Sequence, Animals, COS Cells, Dimerization, Humans, Immunoblotting, Molecular Sequence Data, Muscle, Skeletal, Precipitin Tests, Protein Conformation, Transfection
Actinin, Amino Acid Sequence, Animals, COS Cells, Dimerization, Humans, Immunoblotting, Molecular Sequence Data, Muscle, Skeletal, Precipitin Tests, Protein Conformation, Transfection
Biochem. Biophys. Res. Commun.
Date: Jul. 09, 1998
PubMed ID: 9675099
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