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08:57
Aip1p Dynamics Are Altered by the R256H Mutation in Actin
Published on: July 30, 2014
Differential arginylation of actin isoforms is regulated by coding sequence-dependent degradation.
Fangliang Zhang1, Sougata Saha, Svetlana A Shabalina
1Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Science (New York, N.Y.)
|September 18, 2010
Summary
Arginylation of actin proteins impacts their stability. Arginylated gamma-actin is rapidly degraded due to its translation rate, unlike beta-actin, revealing a novel protein regulation mechanism.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Mammalian beta- and gamma-actin are homologous cytoskeletal proteins.
- Only beta-actin undergoes amino-terminal arginylation in vivo, a process regulating its function.
Purpose of the Study:
- To investigate the metabolic fate of exogenously expressed arginylated and nonarginylated actin isoforms.
- To elucidate the mechanisms underlying the differential stability of arginylated actin isoforms.
Main Methods:
- Expression of arginylated and nonarginylated beta- and gamma-actin isoforms.
- In vivo analysis of protein stability, ubiquitination, and degradation pathways.
Main Results:
- Arginylated gamma-actin exhibited high instability and selective ubiquitination and degradation in vivo, contrasting with beta-actin.
- Differences in nucleotide coding sequences between actin isoforms led to varied translation rates.
- Slower translation of gamma-actin exposed a lysine residue for ubiquitination, targeting it for degradation upon arginylation.
Conclusions:
- Protein arginylation's impact on stability is modulated by isoform-specific translation rates.
- A novel degradation mechanism links nucleotide coding sequence, translation speed, and protein arginylation.
- This pathway may serve as a regulatory mechanism for protein arginylation in vivo.
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