ABA-regulated SNRK2 Protein Kinase: Difference between revisions

From Proteopedia
Jump to navigationJump to search
← Older editNewer edit →
No edit summary
No edit summary
Line 2: Line 2:
Three members of the SnRK2 family of protein kinases - SnRK2.6/OST1/SRK2E, SNRK2.2/SRK2D and SnRK2.3/SRK2I - are activated by the [[ABA Signaling Pathway]]<ref name ="Umezawa2009"> PMID:19805022 </ref><ref name ="Soon2012"> PMID:22116026 </ref><ref name = "Mustilli2002">PMID:12468729</ref><ref>PMID:12514244</ref><ref name = "Nakashima2009">PMID:19541597</ref><ref name = "Fujii2007">PMID:17307925</ref> . SnRK2 stands for <u>Sn</u>f1-<u>r</u>elated protein <u>k</u>inase family, group <u>2</u>. These protein kinases have [[Eukaryotic Protein Kinase Catalytic Domain]]s that are related to yeast Snf1, and they belong to the calmodulin-dependent protein kinase family of the kinome.  
Three members of the SnRK2 family of protein kinases - SnRK2.6/OST1/SRK2E, SNRK2.2/SRK2D and SnRK2.3/SRK2I - are activated by the [[ABA Signaling Pathway]]<ref name ="Umezawa2009"> PMID:19805022 </ref><ref name ="Soon2012"> PMID:22116026 </ref><ref name = "Mustilli2002">PMID:12468729</ref><ref>PMID:12514244</ref><ref name = "Nakashima2009">PMID:19541597</ref><ref name = "Fujii2007">PMID:17307925</ref> . SnRK2 stands for <u>Sn</u>f1-<u>r</u>elated protein <u>k</u>inase family, group <u>2</u>. These protein kinases have [[Eukaryotic Protein Kinase Catalytic Domain]]s that are related to yeast Snf1, and they belong to the calmodulin-dependent protein kinase family of the kinome.  


Two of SnRK2.6/OST1/SRK2E's three names originated from its membership in subclass III of the SnRK2 family of protein kinases. It was named SnRK2.6 by Hrabak et al.<ref>PMID:12805596</ref> and SRK2E by Umezawa et al.<ref name ="Umezawa2009"/>. The third name OST1 (open stomata 1)<ref name = "Mustilli2002"/> is descriptive of the phenotype of plants bearing a gene mutation that produces an inactive protein kinase.  
The best studied ABA-regulated protein kinase is SnRK2.6/OST1/SRK2E. Two of its three names originated from its membership in subclass III of the SnRK2 family of protein kinases. It was named SnRK2.6 by Hrabak et al.<ref>PMID:12805596</ref> and SRK2E by Umezawa et al.<ref name ="Umezawa2009"/>. The third name OST1 (open stomata 1)<ref name = "Mustilli2002"/> is descriptive of the phenotype of plants bearing a gene mutation that produces an inactive protein kinase.  


In rice homologs of these protein kinases are named SAPK8, SAPK9 and SAPK10.
In rice homologs of these protein kinases are named SAPK8, SAPK9 and SAPK10.


==Kinase structure and regulation==
==Kinase regulation and structure==
 
As shown in [[ABA Signaling Pathway]] SnRK2.6/OST1/SRK2E and its homologs are regulated indirectly by ABA. Kinase activity is doubly inhibited in the absence of ABA by its binding to an [[ABA-regulated Protein Phosphatase 2C]]. This interaction results in dephosphorylation of the protein kinase's activation loop and blocking of its active site by phosphatase. When ABA binds to its receptor, the receptor binds to the protein phosphatase, freeing the protein kinase. The kinase is now free to be activated by phosphorylation of its activation loop by either itself or another protein kinase. 


SnRK2.6/OST1/SRK2E has a primary structure comprising an amino terminal [[Eukaryotic Protein Kinase Catalytic Domain]] and a C-terminal sequence that contains the SNRK2 box, which is unique to the SNRK2 family and required for activity<ref name= "Ng2011"/><ref name ="Belin2006"> PMID: 16766677</ref>. Its C-terminus also contains a sequence called the ABA box, which is found only in the family members that are responsive to ABA<ref name ="Belin2006">. The latter sequence is required for binding to PP2C<ref name ="Belin2006">, but is not seen in the crystal structure.
SnRK2.6/OST1/SRK2E has a primary structure comprising an amino terminal [[Eukaryotic Protein Kinase Catalytic Domain]] and a C-terminal sequence that contains the SNRK2 box, which is unique to the SNRK2 family and required for activity<ref name= "Ng2011"/><ref name ="Belin2006"> PMID: 16766677</ref>. Its C-terminus also contains a sequence called the ABA box, which is found only in the family members that are responsive to ABA<ref name ="Belin2006">. The latter sequence is required for binding to PP2C<ref name ="Belin2006">, but is not seen in the crystal structure.
The scenes below explore the structure of SnRK2.6/OST1/SRK2E as a free monomer and in complex with protein phosphatase 2C, HAB1


<ref name ="Soon2013"> PMID:22116026 </ref>
<ref name ="Soon2013"> PMID:22116026 </ref>
Retrieved from "https://proteopedia.org/ABA-regulated_SNRK2_Protein_Kinase"