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Differential arginylation of actin isoforms is regulated by coding sequence-dependent degradation.

ABSTRACT: The mammalian cytoskeletal proteins ?- and ?-actin are highly homologous, but only ?-actin is amino-terminally arginylated in vivo, which regulates its function. We examined the metabolic fate of exogenously expressed arginylated and nonarginylated actin isoforms. Arginylated ?-actin, unlike ?-, was highly unstable and was selectively ubiquitinated and degraded in vivo. This instability was regulated by the differences in the nucleotide coding sequence between the two actin isoforms, which conferred different translation rates. ?-actin was translated more slowly than ?-actin, and this slower processing resulted in the exposure of a normally hidden lysine residue for ubiquitination, leading to the preferential degradation of ?-actin upon arginylation. This degradation mechanism, coupled to nucleotide coding sequence, may regulate protein arginylation in vivo.

SUBMITTER: Zhang F

PROVIDER: S-EPMC2941909 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

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Differential arginylation of actin isoforms is regulated by coding sequence-dependent degradation.

Zhang Fangliang F Saha Sougata S Shabalina Svetlana A SA Kashina Anna A

Science (New York, N.Y.) 20100901 5998

The mammalian cytoskeletal proteins β- and γ-actin are highly homologous, but only β-actin is amino-terminally arginylated in vivo, which regulates its function. We examined the metabolic fate of exogenously expressed arginylated and nonarginylated actin isoforms. Arginylated γ-actin, unlike β-, was highly unstable and was selectively ubiquitinated and degraded in vivo. This instability was regulated by the differences in the nucleotide coding sequence between the two actin isoforms, which confe ...[more]

PMID: 20847274

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