Descripción del proyecto
THE REGULATION OF ION HOMEOSTASIS IN RESPONSE TO CHANGING EXTRACELLULAR ENVIRONMENTS IS A VITAL REQUIREMENT FOR ALL CELLS, WITHIN THIS CONTEXT, THE DYNAMIC REGULATION OF ION TRANSPORTERS AND CHANNELS PRESENT AT THE PLASMA MEMBRANE IS A FIELD OF STUDY WITH GROWING IMPLICATIONS, ESTABLISHMENT OF TESTABLE PARADIGMS IN EXPERIMENTALLY-TRACTABLE MODEL SYSTEMS, SUCH AS THE YEAST SACCHAROMYCES CEREVISIAE IS AN IMPORTANT OBJECTIVE FOR THIS EXPANDING FIELD, OUR GROUP RECENTLY IDENTIFIED A ROLE FOR TWO YEAST PROTEIN KINASES IN THE MAINTENANCE OF THE STABILITY OF NOT ONLY A POTASSIUM TRANSPORTER, BUT ALSO OTHER NUTRIENT PERMEASES AT THE PLASMA MEMBRANE, TOGETHER WITH DEVELOPING INFORMATION FROM BOTH PLANT AND ANIMAL SYSTEMS, THESE RESULTS INDICATE THAT PHOSPHORYLATION-DEPENDENT MECHANISMS OF TRANSPORTER REGULATION ARE LIKELY TO PLAY IMPORTANT ROLES IN ESTABLISHING AND MAINTAINING ION HOMEOSTASIS IN RESPONSE TO CHANGING EXTRACELLULAR ENVIRONMENTS, THE AIM OF THE CURRENT SUBPROJECT IS TO CONTRIBUTE TO THE CHARACTERIZATION OF THESE REGULATORY SYSTEMS THROUGH THE DETERMINATION OF THE MOLECULAR TARGETS AND MECHANISMS OF REGULATION OF TWO RELEVANT YEAST KINASES, HAL4 AND HAL5 AND THE DETAILED ANALYSIS OF RESIDUES IMPLICATED IN THE PHOSPHO- AND UBIQUITIN-DEPENDENT REGULATION OF THE STABILITY OF A MODEL YEAST POTASSIUM TRANSPORTER, TRK1, IN ADDITION, WE PROPOSE TO INVESTIGATE WHETHER SIMILAR MECHANISMS EXIST IN PLANTS, A FEW EXAMPLES OF KINASE-DEPENDENT REGULATION OF ION TRANSPORTERS HAVE BEEN REPORTED IN ARABIDOPSIS THALIANA, BUT THE MECHANISM BY WHICH THESE PHOSPHORYLATION EVENTS AFFECT TRANSPORTER ACTIVITY IS CURRENTLY UNKNOWN, AS A FIRST STEP, WE WILL DETERMINE WHETHER FUNCTIONAL ORTHOLOGS OF THE HAL4 AND HAL5 KINASES ARE PRESENT IN THE ARABIDOPSIS GENOME AND, IF SO, WE WILL FOLLOW STRATEGIES SIMILAR TO THOSE ESTABLISHED IN YEAST TO IDENTIFY THE TARGET PROTEINS OF THESE KINASES, WE WILL ALSO IDENTIFY REGULATORS OF THE CLOSEST PLANT HOMOLOGUE OF TRK1, HKT1 USING THE YEAST TWO-HYBRID SYSTEM, AN APPROACH WHICH HAS BEEN SUCCESSFUL IN THE CASE OF ION CHANNELS AND ANTIPORTERS, THE RESULTS OBTAINED DURING THE COURSE OF THIS RESEARCH WILL CONTRIBUTE TO OUR UNDERSTANDING OF THE MECHANISMS DETERMINING THE DYNAMIC REGULATION OF ION HOMEOSTASIS DURING ADAPTATION TO VARIBLE ENVIRONMENTAL CONDITIONS, transducción de señales\homeostasis iónica\potasio\kinasa\regulación