Open AccessStudying the Involvement of the Linker Protein CWLP and its Homologue in Cytoskeleton-plasma Membrane-cell Wall Continuum and in Drought Tolerance
Author(s) -
Aviah Zilberstein,
Bo Liu,
Einat Sadot
Publication year - 2012
Language(s) - English
Resource type - Reports
DOI - 10.32747/2012.7593387.bard
Subject(s) - aquaporin , microbiology and biotechnology , arabidopsis , biology , cytosol , protein domain , cytoskeleton , lipid raft , cell membrane , membrane , biochemistry , chemistry , biophysics , cell , signal transduction , gene , enzyme , mutant
The study has been focused on proline-rich proteins from the HyPRP family. Three proline-rich proteins have been characterized with the CWLP as the main objective. We showed that this unique protein is assembled in the plasma membrane (PM) and forms a continuum between the cell wall (CW) and cytosol via the PM. While spanning the PM, it is arranged in lipid rafts as CWLP-aquaporin complexes that recruit PP2A-β”, as a part of PP2A enzyme, close to the aquaporin moiety where it dephosphorylates two crucial Ser residues and induces closure of the aquaporin water channels. The closure of water channels renders cells more tolerant to plasmolysis and plants to dehydration. This unique effect was observed not only in Arabidopsis, but also in potato plants over expressing the CWLP, suggesting a possible usage in crop plants as a valve that reduces loss of water or/and elevates cold resistance. The CWLP is a member of the HyPRP protein family that all possess structurally similar 8CM domain, predicted to localize to PM lipid rafts. In this study, two additional highly homologous HyPRP proteins were also studied. The GPRP showed the same localization and it’s over expression increased tolerance to lack of water. However, the third one, PRP940, despite sharing high homology in the 8CM domain, is completely different and is assembled in parallel to cortical microtubules in the cell. Moreover, our data suggest that this protein is not involved in rendering plants resistant to lack of water. We suggest implying CWLP as a tool for better regulation of water maintenance in crop plants.