| Autor: |
Roe, J L, Durfee, T, Zupan, J R, Repetti, P P, McLean, B G, Zambryski, P C |
| Zdroj: |
Journal of Biological Chemistry; February 1997, Vol. 272 Issue: 9 p5838-45, 8p |
| Abstrakt: |
The TOUSLED (TSL) gene is essential for the proper morphogenesis of leaves and flowers in Arabidopsis thaliana. Protein sequence analysis predicts TSL is composed of a carboxyl-terminal protein kinase catalytic domain and a large amino-terminal regulatory domain. TSL fusion proteins, expressed in and purified from yeast, were used to demonstrate TSL protein kinase activity in vitro. TSL trans-autophosphorylates on serine and threonine residues, and phosphorylates exogenous substrates. Using the yeast two-hybrid system, TSL was found to oligomerize via its NH2-terminal domain. A deletion series indicates that a region containing two alpha-helical segments predicted to participate in a coiled-coil structure is essential for oligomerization. TSL localizes to the nucleus in plant cells through an essential NH2-terminal nuclear localization signal; however, this signal is not necessary for protein kinase activity. Finally, deletion mutants demonstrate a strict correlation between catalytic activity and the ability to oligomerize, arguing that activation of the protein kinase requires interaction between TSL molecules. |
| Databáze: |
Supplemental Index |
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