title: Analysis of desiccation-induced candidate phosphoproteins from Craterostigma plantagineum isolated with a modified metal oxide affinity chromatography procedure.
abstract: Reversible protein phosphorylation/dephosphorylation is crucial for regulation of many cellular events, and increasing evidence indicates that this post-translational modification is also involved in the complex process of acquisition of desiccation tolerance. To analyze the phosphoproteome of the desiccation tolerant resurrection plant Craterostigma plantagineum, MOAC-enriched proteins from leaves at different stages of a de-/rehydration cycle were separated by 2-D PAGE and detected by phosphoprotein-specific staining. Using this strategy 20 putative phosphoproteins were identified by MALDI-TOF MS and MS/MS, which were not detected when total proteins were analyzed. The characterized desiccation-related phosphoproteins CDeT11-24 and CDeT6-19 were used as internal markers to validate the specificity of the analyses. For 16 of the identified proteins published evidence suggests that they are phosphoproteins. Comparative analysis of the 2-D gels showed that spot intensities of most identified putative phosphoproteins change during the de-/rehydration cycle. This suggests an involvement of these proteins in desiccation tolerance. Nearly all changes in the phosphoproteome of C. plantagineum, which are triggered by dehydration, are reversed within 4 days of rehydration, which is in agreement with physiological observations. Possible functions of selected proteins are discussed in the context of the de-/rehydration cycle.
authors.affiliation: Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany. hroehrig@uni-bonn.de
authors.forename: Horst
authors.initials: H
authors.lastname: Röhrig
authors.forename: Tom
authors.initials: T
authors.lastname: Colby
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schmidt
authors.forename: Anne
authors.initials: A
authors.lastname: Harzen
authors.forename: Fabio
authors.initials: F
authors.lastname: Facchinelli
authors.forename: Dorothea
authors.initials: D
authors.lastname: Bartels