Rice calcium/calmodulin-dependent protein kinase directly phosphorylates a mitogen-activated protein kinase kinase to regulate abscisic acid responses.
Plant Cell
; 33(5): 1790-1812, 2021 07 02.
Article
em En
| MEDLINE
| ID: mdl-33630095
ABSTRACT
Calcium (Ca2+)/calmodulin (CaM)-dependent protein kinase (CCaMK) is an important positive regulator of abscisic acid (ABA) and abiotic stress signaling in plants and is believed to act upstream of mitogen-activated protein kinase (MAPK) in ABA signaling. However, it is unclear how CCaMK activates MAPK in ABA signaling. Here, we show that OsDMI3, a rice (Oryza sativa) CCaMK, directly interacts with and phosphorylates OsMKK1, a MAPK kinase (MKK) in rice, in vitro and in vivo. OsDMI3 was found to directly phosphorylate Thr-25 in the N-terminus of OsMKK1, and this Thr-25 phosphorylation is OsDMI3-specific in ABA signaling. The activation of OsMKK1 and its downstream kinase OsMPK1 is dependent on Thr-25 phosphorylation of OsMKK1 in ABA signaling. Moreover, ABA treatment induces phosphorylation in the activation loop of OsMKK1, and the two phosphorylations, in the N-terminus and in the activation loop, are independent. Further analyses revealed that OsDMI3-mediated phosphorylation of OsMKK1 positively regulates ABA responses in seed germination, root growth, and tolerance to both water stress and oxidative stress. Our results indicate that OsMKK1 is a direct target of OsDMI3, and OsDMI3-mediated phosphorylation of OsMKK1 plays an important role in activating the MAPK cascade and ABA signaling.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
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Oryza
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Cálcio
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Ácido Abscísico
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Proteínas Quinases Dependentes de Cálcio-Calmodulina
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Quinases de Proteína Quinase Ativadas por Mitógeno
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article