RRC ID 28738
Author Ishii K, Nakao Y, Amagai A, Maeda Y.
Title Novel functions of ribosomal protein S6 in growth and differentiation of Dictyostelium cells.
Journal Dev. Growth Differ.
Abstract We have previously shown that in Dictyostelium cells a 32 kDa protein is rapidly and completely dephosphorylated in response to starvation that is essential for the initiation of differentiation (Akiyama & Maeda 1992). In the present work, this phosphoprotein was identified as a homologue (Dd-RPS6) of ribosomal protein S6 (RPS6) that is an essential member for protein synthesis. As expected, Dd-RPS6 seems to be absolutely required for cell survival, because we failed to obtain antisense-RNA mediated cells as well as Dd-rps6-null cells by homologous recombination in spite of many trials. In many kinds of cell lines, RPS6 is known to be located in the nucleus and cytosol, but Dd-RPS6 is predominantly located in the cell cortex with cytoskeletons, and in the contractile ring of just-dividing cells. In this connection, the overexpression of Dd-RPS6 greatly impairs cytokinesis during axenic shake-cultures in growth medium, resulting in the formation of multinucleate cells. Much severe impairment of cytokinesis was observed when Dd-RPS6-overexpressing cells (Dd-RPS6(OE) cells) were incubated on a living Escherichia coli lawn. The initiation of differentiation triggered by starvation was also delayed in Dd-RPS6(OE) cells. In addition, Dd-RPS6(OE) cells exhibit defective differentiation into prespore cells and spores during late development. Thus, it is likely that the proper expression of Dd-RPS6 may be of importance for the normal progression of late differentiation as well as for the initiation of differentiation.
Volume 51(6)
Pages 533-46
Published 2009-8
DOI 10.1111/j.1440-169X.2009.01115.x
PMID 21314671
MeSH Blotting, Western Cell Cycle Cell Differentiation Cell Proliferation Cytokinesis Dictyostelium / cytology Dictyostelium / genetics Dictyostelium / physiology* Fluorescent Antibody Technique Gene Expression Phosphorylation Protozoan Proteins / genetics Protozoan Proteins / physiology* Ribosomal Protein S6 / genetics Ribosomal Protein S6 / physiology* Starvation
IF 1.638
Times Cited 3
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