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| Title: Abscisic acid-activated SNRK2 protein kinases function in the gene-regulation pathway of ABA signal transduction by phosphorylating ABA response element-binding factors .
| | Author: Kobayashi Y Murata M Minami H Yamamoto S Kagaya Y Hobo T Yamamoto A Hattori T | | Journal: Plant J Citation: V : 44 ( 6 ) P : 939-49 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16359387 Accession (PMID): 16359387 | | Abstract: The plant hormone abscisic acid ( ABA ) induces gene expression via the ABA-response element ( ABRE ) present in the promoters of ABA-regulated genes .
A group of bZIP proteins have been identified as ABRE-binding factors ( ABFs ) that activate transcription through this cis element .
A rice ABF , TRAB1 , has been shown to be activated via ABA-dependent phosphorylation .
While a large number of signalling factors have been identified that are involved in stomatal regulation by ABA , relatively less is known about the ABA-signalling pathway that leads to gene expression .
We have shown recently that three members of the rice SnRK2 protein kinase family , SAPK8 , SAPK9 and SAPK10 , are activated by ABA signal as well as by hyperosmotic stress .
Here we show that transient overexpression in cultured cell protoplasts of these ABA-activated SnRK2 protein kinases leads to the activation of an ABRE-regulated promoter , suggesting that these kinases are involved in the gene-regulation pathway of ABA signalling .
We further show several lines of evidence that these ABA-activated SnRK2 protein kinases directly phosphorylate TRAB1 in response to ABA .
Kinetic analysis of SAPK10 activation and TRAB1 phosphorylation indicated that the latter immediately followed the former .
TRAB1 was found to be phosphorylated not only in response to ABA , but also in response to hyperosmotic stress , which was interpreted as the consequence of phosphorylation of TRAB1 by hyperosmotically activated SAPKs .
Physical interaction between TRAB1 and SAPK10 in vivo was demonstrated by a co-immunoprecipitation experiment .
Finally , TRAB1 was phosphorylated in vitro by the ABA-activated SnRK2 protein kinases at Ser102 , which is phosphorylated in vivo in response to ABA and is critical for the activation function . | Matching Sentences:
[ Sen. 5, subscore: 1.00 ]: We have shown recently that three members of the rice SnRK2 protein kinase family , SAPK8 , SAPK9 and SAPK10 , are activated by ABA signal as well as by hyperosmotic stress .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
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| Title: Cloning and characterization of a maize SnRK2 protein kinase gene confers enhanced salt tolerance in transgenic Arabidopsis .
| | Author: Ying S Zhang DF Li HY Liu YH Shi YS Song YC Wang TY Li Y | | Journal: Plant Cell Rep Citation: V : 30 P : 1683-99 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub21638061 Accession (PMID): 21638061 | | Abstract: SnRK2 ( sucrose non-fermenting 1-related protein kinases 2 ) represents a unique family of protein kinase in regulating signaling transduction in plants .
Although the regulatory mechanisms of SnRK2 have been well demonstrated in Arabidopsis thaliana , their functions in maize are still unknown .
In our study , we cloned an SnRK2 gene from maize , ZmSAPK8 , which encoded a putative homolog of the rice SAPK8 protein .
ZmSAPK8 had two copies in the maize genome and harbored eight introns in its coding region .
We demonstrated that ZmSAPK8 expressed differentially in various organs of maize plants and was up-regulated by high-salinity and drought treatment .
A green fluorescent protein ( GFP ) -tagged ZmSAPK8 showed subcellular localization in the cell membrane , cytoplasm and nucleus .
In vitro kinase assays indicated that ZmSAPK8 preferred Mn ( 2+ ) to Mg ( 2+ ) as cofactor for phosphorylation , and Ser-182 and Thr-183 in activation loop was important for its activity .
Heterologous overexpression of ZmSAPK8 in Arabidopsis could significantly strengthen tolerance to salt stress .
Under salt treatment , ZmSAPK8-overexpressed transgenic plants exhibited higher germination rate and proline content , low electrolyte leakage and higher survival rate than wild type .
Further analysis indicated that transgenic plants showed increased transcription of the stress-related genes , RD29A , RD29B , RAB18 , ABI1 , DREB2A and P5CS1 , under high-salinity conditions .
The results demonstrated that ZmSAPK8 was involved in diverse stress signal transduction .
Moreover , no obvious adverse effects on growth and development in the ZmSAPK8-overexpressed transgenic plants implied that ZmSAPK8 was potentially useful in transgenic breeding to improve salt tolerance in crops .
| Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: In our study , we cloned an SnRK2 gene from maize , ZmSAPK8 , which encoded a putative homolog of the rice SAPK8 protein .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
