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Myopalladin, a novel 145-kilodalton sarcomeric protein with multiple roles in Z-disc and I-band protein assemblies.

ABSTRACT: We describe here a novel sarcomeric 145-kD protein, myopalladin, which tethers together the COOH-terminal Src homology 3 domains of nebulin and nebulette with the EF hand motifs of alpha-actinin in vertebrate Z-lines. Myopalladin's nebulin/nebulette and alpha-actinin-binding sites are contained in two distinct regions within its COOH-terminal 90-kD domain. Both sites are highly homologous with those found in palladin, a protein described recently required for actin cytoskeletal assembly (Parast, M.M., and C.A. Otey. 2000. J. Cell Biol. 150:643-656). This suggests that palladin and myopalladin may have conserved roles in stress fiber and Z-line assembly. The NH(2)-terminal region of myopalladin specifically binds to the cardiac ankyrin repeat protein (CARP), a nuclear protein involved in control of muscle gene expression. Immunofluorescence and immunoelectron microscopy studies revealed that myopalladin also colocalized with CARP in the central I-band of striated muscle sarcomeres. Overexpression of myopalladin's NH(2)-terminal CARP-binding region in live cardiac myocytes resulted in severe disruption of all sarcomeric components studied, suggesting that the myopalladin-CARP complex in the central I-band may have an important regulatory role in maintaining sarcomeric integrity. Our data also suggest that myopalladin may link regulatory mechanisms involved in Z-line structure (via alpha-actinin and nebulin/nebulette) to those involved in muscle gene expression (via CARP).

SUBMITTER: Bang ML

PROVIDER: S-EPMC2169455 | biostudies-literature | 2001 Apr

REPOSITORIES: biostudies-literature

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Myopalladin, a novel 145-kilodalton sarcomeric protein with multiple roles in Z-disc and I-band protein assemblies.

Bang M L ML Mudry R E RE McElhinny A S AS Trombitás K K Geach A J AJ Yamasaki R R Sorimachi H H Granzier H H Gregorio C C CC Labeit S S

The Journal of cell biology 20010401 2

We describe here a novel sarcomeric 145-kD protein, myopalladin, which tethers together the COOH-terminal Src homology 3 domains of nebulin and nebulette with the EF hand motifs of alpha-actinin in vertebrate Z-lines. Myopalladin's nebulin/nebulette and alpha-actinin-binding sites are contained in two distinct regions within its COOH-terminal 90-kD domain. Both sites are highly homologous with those found in palladin, a protein described recently required for actin cytoskeletal assembly (Parast, ...[more]

PMID: 11309420

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Dataset Information

Myopalladin, a novel 145-kilodalton sarcomeric protein with multiple roles in Z-disc and I-band protein assemblies.

Publications

Myopalladin, a novel 145-kilodalton sarcomeric protein with multiple roles in Z-disc and I-band protein assemblies.

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