Project aims

Ca²⁺  signals  are  core  transducers  and  regulators  in  many  adaptation  and developmental processes of plants. Ca²⁺ signals are represented by stimulus-specific signatures that result from the concerted action of channels, pumps and carriers that shape  temporally  and  spatially  defined  Ca²⁺  elevations.  Cellular  Ca²⁺  signals  are decoded  and  transmitted  by  a  toolkit  of Ca²⁺-binding  proteins  that  relay  this  information  into  downstream  response  reactions.  Major  transduction  routes  of  Ca²⁺ signaling  involve  Ca²⁺  regulated  kinases  mediating  phosphorylation  events  that orchestrate downstream responses. The functional interconnection of Ca²⁺ signaling and  phosphorylation-dependent  regulation  of  biological  processes  represents  the central and connecting theme of this Research Unit.

The  Research  Unit  therefore  combines  experts  in  the  fields  of  Ca²⁺-dependent protein  phosphorylation,  mass-spectrometry  and  membrane  transport  to  achieve  a detailed  and  integrative  understanding  of  calcium  and  phosphorylation  mediated modulation of biological regulatory circuits. During the last funding period this Unit has successfully pursued the following general scientific aims:

1. Characterization of components and mechanisms leading to localized and transient changes in (sub-)cellular Ca²⁺ concentration
   
   
2. Analysis  of  contribution  of  different  sub-cellular  compartments  as  sources  and reservoirs for Ca²⁺ signaling
   
   
3. Investigation  of  the function  and  regulation  of  Ca²⁺-dependent kinases and  their interactions with other signaling components
   
   
4. Identification and characterization of targets of Ca²⁺-dependent protein kinases

Based on the resources, tools and most exciting scientific insights that we obtained and  generated  during  the  last  funding  period  the  members  of  this  Resaerch Unit  have  now targeted a novel and most advanced strategic goal for the requested funding period:

“The  in  vivo  and  in  vitro  analysis  and  reconstitution  of  Ca²⁺-regulated  signaling pathways”

In  order  to  achieve  this  goal  we  will  further  develop  and  pursue  several
complementary  approaches:

1. We  will  use  our  advanced  Ca²⁺  reporter  protein systems for investigation of Ca²⁺ dynamics in several model systems at high tissue-specific  and  sub-cellular  resolution  and  will  further  extend  our  Ca²⁺  reporter  protein toolkit.
2. We  will  further  dissect  the  role  of  phosphorylation  of  the  CCaMK  target CYCLOPS  for  organogenesis  and  symbiotic  infection  and  will  investigate  the crosstalk  between  nodulation  and  ABA  signaling.
3. A  central  scientific  question addressed by several groups of the Research Unit will be the modulation and interconnection of hormone  perception  by Ca²⁺-regulated  kinases/phosphatases.  Here,  the  ABA signaling  system  will  represent  a  prominent  model  system  but  also  the interconnection  to  jasmonate  signaling  will  be  addressed.  We  will  pursue  several complementary  approaches  and  will  apporach  the  simultaneous  reconstitution  of complete ABA signaling pathways and their interacting Ca²⁺ signaling components in models  systems  such  as  yeast,  Xenopus  oocytes  and  in  vitro.
4. The  functional characterization  of  Ca²⁺-regulated  ion  transport  processes  and  transcriptional responses.  Here,  in  addition  to  investigate  the  interplay  of phosphorylation/dephosphorylation in regulation of target proteins, a most interesting novel  aspect  will  be  the  interconnection  of  CDPK  and  CIPK  mediated  target phosphorylation
5. We  will  perform mass-spectrometry  based  phosphorylation  site mapping on kinases and kinase substrates to enable the functional characterization of  the  role  of  these  phosphorylations  and  will  perform  non-biased  kinase  target identification by comparative phospho-proteomics analysis.

Further informations:

Scientific Background
Results of 1. Funding Period
Future Goals
International Representation

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