PUBLICATION
Biochemical consequences of the cardiofunk (R177H) mutation in yeast actin
- Authors
- Wen, K.K. and Rubenstein, P.A.
- ID
- ZDB-PUB-030919-7
- Date
- 2003
- Source
- The Journal of biological chemistry 278(48): 48386-48394 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Actins/chemistry
- Actins/genetics*
- Heterozygote
- Hydrogen Bonding
- Hydrogen-Ion Concentration
- Kinetics
- Microscopy, Electron
- Models, Chemical
- Mutagenesis, Site-Directed
- Mutation*
- Myocardium/metabolism
- Oligonucleotides/chemistry
- Phosphates/chemistry
- Protein Conformation
- Pyrenes/chemistry
- Temperature
- Time Factors
- Tropomyosin/chemistry
- Tropomyosin/metabolism
- Yeasts/metabolism*
- PubMed
- 13129918 Full text @ J. Biol. Chem.
Citation
Wen, K.K. and Rubenstein, P.A. (2003) Biochemical consequences of the cardiofunk (R177H) mutation in yeast actin. The Journal of biological chemistry. 278(48):48386-48394.
Abstract
The zebrafish cardiofunk actin mutation, R(177)H, causes abnormal heart development. We have introduced this mutation into yeast actin to assess its biochemical consequences. R(177)H G-actin exhibited reduced thermal stability and an accelerated nucleotide exchange rate. R(177)H actin has an increased critical concentration and polymerizes with a greatly extended nucleation phase but a faster elongation process, suggesting that significant fragmentation accompanies filament formation. Pi release from R(177)H actin is tightly coupled to polymerization, as with WT actin, suggesting that the R(177)H mutation does not affect ATPase activity and Pi release. R(177)H actin shows no polymerization-dependent decrease in intrinsic Trp fluorescence, and the fluorescence yield of a pyrene at C(374) is decreased. An equivalent amount of WT actin significantly but not completely rescues the mutants polymerization defect. Tropomyosin greatly exacerbates the elongation of the nucleation phase of R(177)H actin but slightly decreases its critical concentration. It has only a slight effect on a 1:1 WT/mutant mixture. The defects we observed with R(177)H actin in vitro indicate that R(177) is crucial for the control of the structural integrity of the actin monomer and the actin filament, and provide insight into the defects caused by this mutation in zebrafish cardiogenesis.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping