| Structural highlights
Function
SRK2E_ARATH Activator of the abscisic acid (ABA) signaling pathway that regulates numerous ABA responses, such as stomata closure in response to drought, plant pathogens, or decreases in atmospheric relative humidity (RH). Involved in the resistance to drought by avoiding water loss. Required for the stomata closure mediated by pathogen-associated molecular pattern (PAMPs) (e.g. flg22 and LPS) of pathogenic bacteria such as P.syringae pv. tomato (Pst) and E.coli O157:H7. As a plant defense process, stomata are closed transiently in order to limit invaders, but actively reopened by bacteria after a few hours; virulent strains (e.g. Pst DC3000) are more efficient than avirulent strains (e.g. Pst DC3000 AvrRpt2) in reopening stomata. Mediates the phosphorylation and activation of the S-type anion efflux channel SLAC1, and thus promotes stomata closure. Essential for stomatal closure in response to reactive oxygen species (ROS).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
Publication Abstract from PubMed
SnRK [SNF1 (sucrose non-fermenting-1)-related protein kinase] 2.6 [open stomata 1 (OST1)] is well characterized at molecular and physiological levels to control stomata closure in response to water-deficit stress. OST1 is a member of a family of 10 protein kinases from Arabidopsis thaliana (SnRK2) that integrates abscisic acid (ABA)-dependent and ABA-independent signals to coordinate the cell response to osmotic stress. A subgroup of protein phosphatases type 2C binds OST1 and keeps the kinase dephosphorylated and inactive. Activation of OST1 relies on the ABA-dependent inhibition of the protein phosphatases type 2C and the subsequent self-phosphorylation of the kinase. The OST1 ABA-independent activation depends on a short sequence motif that is conserved among all the members of the SnRK2 family. However, little is known about the molecular mechanism underlying this regulation. The crystallographic structure of OST1 shows that ABA-independent regulation motif stabilizes the conformation of the kinase catalytically essential alpha C helix, and it provides the basis of the ABA-independent regulation mechanism for the SnRK2 family of protein kinases.
The Structure of Arabidopsis thaliana OST1 Provides Insights into the Kinase Regulation Mechanism in Response to Osmotic Stress.,Yunta C, Martinez-Ripoll M, Zhu JK, Albert A J Mol Biol. 2011 Nov 18;414(1):135-44. Epub 2011 Oct 1. PMID:21983340[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Mustilli AC, Merlot S, Vavasseur A, Fenzi F, Giraudat J. Arabidopsis OST1 protein kinase mediates the regulation of stomatal aperture by abscisic acid and acts upstream of reactive oxygen species production. Plant Cell. 2002 Dec;14(12):3089-99. PMID:12468729
- ↑ Yoshida R, Hobo T, Ichimura K, Mizoguchi T, Takahashi F, Aronso J, Ecker JR, Shinozaki K. ABA-activated SnRK2 protein kinase is required for dehydration stress signaling in Arabidopsis. Plant Cell Physiol. 2002 Dec;43(12):1473-83. PMID:12514244
- ↑ Merlot S, Mustilli AC, Genty B, North H, Lefebvre V, Sotta B, Vavasseur A, Giraudat J. Use of infrared thermal imaging to isolate Arabidopsis mutants defective in stomatal regulation. Plant J. 2002 Jun;30(5):601-9. PMID:12047634
- ↑ Suhita D, Raghavendra AS, Kwak JM, Vavasseur A. Cytoplasmic alkalization precedes reactive oxygen species production during methyl jasmonate- and abscisic acid-induced stomatal closure. Plant Physiol. 2004 Apr;134(4):1536-45. Epub 2004 Apr 2. PMID:15064385 doi:http://dx.doi.org/10.1104/pp.103.032250
- ↑ Melotto M, Underwood W, Koczan J, Nomura K, He SY. Plant stomata function in innate immunity against bacterial invasion. Cell. 2006 Sep 8;126(5):969-80. PMID:16959575 doi:http://dx.doi.org/S0092-8674(06)01015-4
- ↑ Xie X, Wang Y, Williamson L, Holroyd GH, Tagliavia C, Murchie E, Theobald J, Knight MR, Davies WJ, Leyser HM, Hetherington AM. The identification of genes involved in the stomatal response to reduced atmospheric relative humidity. Curr Biol. 2006 May 9;16(9):882-7. PMID:16682349 doi:http://dx.doi.org/S0960-9822(06)01324-8
- ↑ Yoshida R, Umezawa T, Mizoguchi T, Takahashi S, Takahashi F, Shinozaki K. The regulatory domain of SRK2E/OST1/SnRK2.6 interacts with ABI1 and integrates abscisic acid (ABA) and osmotic stress signals controlling stomatal closure in Arabidopsis. J Biol Chem. 2006 Feb 24;281(8):5310-8. Epub 2005 Dec 19. PMID:16365038 doi:M509820200
- ↑ Belin C, de Franco PO, Bourbousse C, Chaignepain S, Schmitter JM, Vavasseur A, Giraudat J, Barbier-Brygoo H, Thomine S. Identification of features regulating OST1 kinase activity and OST1 function in guard cells. Plant Physiol. 2006 Aug;141(4):1316-27. Epub 2006 Jun 9. PMID:16766677 doi:pp.106.079327
- ↑ Fujii H, Verslues PE, Zhu JK. Identification of two protein kinases required for abscisic acid regulation of seed germination, root growth, and gene expression in Arabidopsis. Plant Cell. 2007 Feb;19(2):485-94. Epub 2007 Feb 16. PMID:17307925 doi:tpc.106.048538
- ↑ Lee SC, Lan W, Buchanan BB, Luan S. A protein kinase-phosphatase pair interacts with an ion channel to regulate ABA signaling in plant guard cells. Proc Natl Acad Sci U S A. 2009 Dec 15;106(50):21419-24. doi:, 10.1073/pnas.0910601106. Epub 2009 Dec 2. PMID:19955427 doi:http://dx.doi.org/10.1073/pnas.0910601106
- ↑ Geiger D, Scherzer S, Mumm P, Stange A, Marten I, Bauer H, Ache P, Matschi S, Liese A, Al-Rasheid KA, Romeis T, Hedrich R. Activity of guard cell anion channel SLAC1 is controlled by drought-stress signaling kinase-phosphatase pair. Proc Natl Acad Sci U S A. 2009 Dec 15;106(50):21425-30. doi:, 10.1073/pnas.0912021106. Epub 2009 Dec 2. PMID:19955405 doi:10.1073/pnas.0912021106
- ↑ Vahisalu T, Puzorjova I, Brosche M, Valk E, Lepiku M, Moldau H, Pechter P, Wang YS, Lindgren O, Salojarvi J, Loog M, Kangasjarvi J, Kollist H. Ozone-triggered rapid stomatal response involves the production of reactive oxygen species, and is controlled by SLAC1 and OST1. Plant J. 2010 May;62(3):442-53. doi: 10.1111/j.1365-313X.2010.04159.x. Epub 2010 , Feb 1. PMID:20128877 doi:http://dx.doi.org/10.1111/j.1365-313X.2010.04159.x
- ↑ Yunta C, Martinez-Ripoll M, Zhu JK, Albert A. The Structure of Arabidopsis thaliana OST1 Provides Insights into the Kinase Regulation Mechanism in Response to Osmotic Stress. J Mol Biol. 2011 Nov 18;414(1):135-44. Epub 2011 Oct 1. PMID:21983340 doi:10.1016/j.jmb.2011.09.041
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