Different protein kinase families are activated by osmotic stresses in Arabidopsis thaliana cell suspensions. Involvement of the MAP kinases AtMPK3 and AtMPK6.
Five Ca(2+)-independent protein kinases were rapidly activated by hypoosmotic stress, moderate or high hyperosmolarity induced by several osmolytes, sucrose, mannitol or NaCl. Three of these kinases, transiently activated by hypoosmolarity, recognised by anti-phosphorylated mitogen-activated protein (MAP) kinase antibodies, sensitive to a MAP kinase inhibitor and inactivated by the action of a tyrosine phosphatase, corresponded to MAP kinases. Using specific antibodies, two of the MAP kinases were identified as AtMPK6 and AtMPK3. The two other protein kinases, durably activated by high hyperosmolarity, did not belong to the MAP kinase family. Activation of AtMPK6 and AtMPK3 by hypoosmolarity depended on upstream protein kinases sensitive to staurosporine and on calcium influx. In contrast, these two transduction steps were not involved in the activation of the two protein kinases activated by high hyperosmolarity.
Droillard
Marie
M
Institut des Sciences du Végétal, UPR 2355, CNRS, 1 av. de la terrasse, 91198 Cedex, Gif s/Yvette, France.
Boudsocq
Marie
M
Barbier-Brygoo
Hélène
H
Laurière
Christiane
C
D000595:Amino Acid Sequence; D047310:Apigenin; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D054642:Dual Specificity Phosphatase 6; D004789:Enzyme Activation; D005419:Flavonoids / Q000494:pharmacology; D008353:Mannitol / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010749:Phosphoprotein Phosphatases; D011494:Protein Kinases / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology; D013535:Suspensions
D029681:Arabidopsis Proteins; D005419:Flavonoids; D008869:Microtubule-Associated Proteins; D013535:Suspensions; D008353:Mannitol; D012965:Sodium Chloride; D047310:Apigenin; D011494:Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054642:Dual Specificity Phosphatase 6; D017027:Protein Tyrosine Phosphatases; D002118:Calcium