Plants, MEN and SIN.
In fission yeast, the onset of septation is signalled through the septum initiation network (SIN) signaling pathway. Similarly, in budding yeast the onset of budding is signalled through the mitotic exit network (MEN) pathway. We previously characterized in Arabidopsis signaling elements (GTPases, kinases) closely related to the core elements (spg1p/TEM1p, cdc7p/CDC15p) of the SIN and MEN pathways. Our first results suggested that a plant signaling pathway must be used to coordinate mitotic exit with cytokinesis. This review questioned the value of such an hypothesis in a multicellular organism. The core elements (G-protein, kinase) of the SIN and MEN pathways were only detected in fungi, plants and Mycetozoa. We also noticed that AtSGP GTPase and AtMAP3Kepsilon kinase revealed two paralogues in Arabidopsis. Although Arabidopsis genes complement fission yeast mutants, and Arabidopsis proteins interact with fission yeast proteins, plants do not use these core elements to coordinate the termination of cell division with cytokinesis. Transcriptional regulation and expression data suggest a function for the plant SIN-like elements in the control of cell type specification. Exploring the evolutionary conservation of an ancient signaling pathway provides evidence that evolution has recycled regulatory elements for elaborating a new signaling avenue.
Laboratoire Cycle Cellulaire, Développement et Différenciation, Institut de Biotechnologie des Plantes, UMR 8618, Batiment 630, Universite Paris XI, Orsay, France.
Mariette
M
Bedhomme
Stefan
S
Jouannic
Antony
A
Champion
Viesturs
V
Simanis
Yves
Y
Henry
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D048749:Cytokinesis / Q000502:physiology*; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D008938:Mitosis / Q000502:physiology*; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; D020559:Monomeric GTP-Binding Proteins