The family of Ste20-like kinases and their subfamilies.
D. discoideum has 11 representatives (see Figure 1) of PAK, GCK II, III, (V?) and VI subfamilies. Additionally, it contains six Ste20-like kinases in two species specific subfamilies, PAK-like and Ste20-DD1 (Arasada et al., 2006; Goldberg et al., 2006).
The Schleicher group is currently working with 13 Ste20-kinases (excluding the Paks A to D) that have a possible regulatory domain C-terminal of the kinase domain, usually a hallmark for GCK-subfamily kinases. To elucidate the function of these kinases we are analyzing the phenotypes of knockouts and GFP-fusion proteins. So far, we were NOT successful in knocking out Krs2 (DDB0216375), a protein that contains four repeats of a calpain-domain-III, and PakG (DDB0229411). For the other 11 Ste20-like kinases knockout mutants have been isolated.
A nomenclature for 17 Ste20-like kinase in Dictyostelium discoideum
|DictyBase ID/gene name||protein Name||comment|
|DDB0216375/krsB||Krs2||contains 4x Calpain-domain III|
|DDB0229414/pakE||PakE||contains PDB/CRIB domain|
|DDB0229410/pakF||PakF||contains PDB/CRIB domain|
|DDB0229411/pakG||PakG||contains PDB/CRIB domain|
|DDB0229408/pakH||PakH||contains PDB/CRIB domain|
The nomenclature is based on phylogenetic relationships. Dst stands for Dictyostelium Ste20-like kinase and should make association to the well characterized MSTs in higher organisms. PakE to PakG is the nomenclature suggested by Goldberg et al. based on the presence of functional PBD/CRIB domains N-terminal of the kinase domain. DFray names the D. discoideum homologs of the drosophila kinase fray.
Sevkin - The first member of Ste20-like kinases in D. discoideum
Sevkin was shown to phosphorylate the actin fragmenting protein severin in vitro (Eichinger et al., 1998). The Schleicher group is currently characterizing the knockout phenotype. More soon ...
Arasada, R., Son, H., Ramalingam, N., Eichinger, L., Schleicher, M., and Rohlfs, M. (2006). Characterization of the Ste20-like kinase Krs1 of Dictyostelium discoideum. Eur. J. Cell Biol., in press. []
Eichinger, L., Bahler, M., Dietz, M., Eckerskorn, C., and Schleicher, M. (1998). Characterization and cloning of a Dictyostelium Ste20-like protein kinase that phosphorylates the actin-binding protein severin. J. Biol. Chem. 273, 12952-12959. []
Goldberg, J.M., Manning, G., Liu, A., Fey, P., Pilcher, K.E., Xu, Y., and Smith, J.L. (2006). The dictyostelium kinome--analysis of the protein kinases from a simple model organism. PLoS Genet. 2, e38. []
Meino Rohlfs, August 2006
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