signal integration and developmental control via multistep
TRANSCRIPT
Signal Integration and Developmental Control via Multistep Phosphorelay Signaling in Plants Jan HejátkoResearch Group Leader
Bratislava, Sep 14 2018
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Outline
Multistep Phosphorelay - Not Only CytokininSignaling in Plants
CKI1 Controls both Gametophyte andSporophyte Development in Arabidopsis
Light – Regulated Expression of CKI1Modulates Cytokinin Sensitivity
Structural Determinants of MSP SignalingSpecificity in Plants
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Signal Transduction via MSP
NUCLEUS
PM
AHK Sensor Histidine Kinases• AHK2 • AHK3• AHK4
REGULATION OF TRANSCRIPTION
INTERACTION WITH EFFECTOR PROTEINS
HPt Proteins• AHP1-6
Response Regulators• ARR1-24
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Complexity in MSP Signaling
AHK2, AHK3, AHK4
AHP1-6
CKI1
NUCLEUS
CONST.ACTIVE
Hwang and Sheen , Nature (2001)Hejátko et al., Plant Cell (2009)
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Outline
Multistep Phosphorelay - Not Only CytokininSignaling in Plants
CKI1 Controls both Gametophyte andSporophyte Development in Arabidopsis
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CKI1 Regulates Female Gametophyte Development
CKI1/CKI1CKI1/cki1-i
Hejátko et al., Mol Genet Genomics (2003)
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CKI1 cki1-i
CKI1 Regulates Female Gametophyte Development
Hejátko et al., Mol Genet Genomics (2003)
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FG0-FG1FG0-FG1FG0-FG1FG3-FG4FG3-FG4FG3-FG4
FG4-FG5FG4-FG5FG4-FG5FG7FG7FG7
Hejátko et al., Mol Genet Genomics (2003)
CKI1 is Expressed Throughout Megagametogenesis
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CKI1 is Active in Arabidopsis Gametophyte and Sporophyte
Hejátko et al., Plant Cell (2009)
αCKI1RD
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CKI1 Regulates Arabidopsis Vascular Stem Cell Activity
Hejátko et al., Plant Cell (2009)
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Complexity in MSP Signaling
AHK2, AHK3, AHK4
AHP1-6
CKI1
NUCLEUS
CONST.ACTIVE
CKI1
X ?
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Outline
Multistep Phosphorelay - Not Only CytokininSignaling in Plants
CKI1 Controls both Gametophyte andSporophyte Development in Arabidopsis
Light – Regulated Expression of CKI1Modulates Cytokinin Sensitivity
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Automated Microscopy Screening
Dobisova and Hejatko, , Methods in Mol Biol, 2014
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LPH Controls Expression of CKI1
Dobisova et al., Plant Physiol, 2017
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lph is novel allele of HEME OXYGENASE 1
Dobisova et al., Plant Physiol, 2017
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lph is Novel Allele of HEME OXYGENASE 1
Terry et al., Biochem Soc Trans, 2002
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Light Controls Spatiotemporal Specificity of CKI1 Expression
Dobisova et al., Plant Phys, 2017
WT
Short Day
Darkness
Red
Far-Red
lph/hy1-7
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CKI1 is Direct Target of Light Sensor phyA
Dobisova et al., Plant Phys, 2017
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CKI1 acts Downstream of phyA
Dobisova et al., Plant Phys, 2017
WT
Short Day
Darkness
Red
Far-Red
phyA
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Does Light-Controlled CKI1 Modulate Cytokinin Signaling?
AHK2, AHK3, AHK4
AHP1-6
CKI1
NUCLEUS
CONST.ACTIVE
CKI1
LIGHT ?
D’Agostino et al., Plant Physiology (2000)
ARRs-A
REGULATION OF TRANSCRIPTION
21Dobisova et al., Plant Physiol, 2017
Light-Regulated CKI1 Expression Controls Cytokinin Signaling
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Light Controls Root Sensitivity to Cytokinins
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Model for light- and development-specific regulation of CKI1
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Outline
Multistep Phosphorelay - Not Only CytokininSignaling in Plants
CKI1 Controls both Gametophyte andSporophyte Development in Arabidopsis
Light – Regulated Expression of CKI1Modulates Cytokinin Sensitivity
Structural Determinants of MSP SignalingSpecificity in Plants
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The results are unpublished, sorry for not showing them in the pdf version of the presentation.
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Conclusions
MSP signaling integrates several signalingpathways of both intrinsic and environmentalorigin
Although MSP displays partial promiscuity,certain specificity is retained
Signaling specificity is determined at the level ofHK receiver domain and HPt protein structure
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AcknowledgementsCEITEC and National Centre forBiomolecular Research, MasarykUniversityFunctional Genomics and Proteomics ofPlantsSiarhei DabravolskiOksana DegtjarikTereza DobisováRadka DopitováZuzana GelováRomana HejátkováJakub HorákVendula HrdinováEliška NejedláBlanka PekárováMarkéta PernisováAgnieszka SzmitkowskaMarkéta Žďárská
Biomolecular NMR SpectroscopyLubomír JandaJozef HritzZuzana JaseňákováOlga Třísková/OtrusinováLukáš ŽídekVladimír Sklenář
X-ray CrystallographyJaromír MarekTomáš Klumpler
University of South Bohemia andAcademy of Sciences of the CzechRepublic. Nové Hrady Oksana Degtjarik Michal Kutý David Řeha Ivana Smatanová-Kutá
VIB Gent and IST Austria Eva Benková Candela Cuesta
University Tuebingen Klaus Harter Michael Heunemann
CALTECH Elliot Meyerowitz Paul Tarr
Thank you for your attention
Central European Institute of TechnologyMasaryk UniversityKamenice 753/5 625 00 Brno, Czech Republic
www.ceitec.muni.cz | [email protected]