Abstract
Upon cold acclimation, freezing tolerance of Arabidopsis thaliana increases significantly. Cold acclimation results in changes in protein composition and decreases in sphingolipids (i.e., cerebrosides) in the plasma membrane. In the plasma membrane of animal cells, proteins associated with sphingolipid- and cholesterol-rich detergent-resistant membrane (DRM) microdomain, are known to play important roles in signal transduction and pathogenesis. To investigate whether DRM-associated proteins involve in freezing tolerance in plants, we here determined expression patterns of DRM-associated proteins during cold acclimation. A DRM fraction was obtained by sucrose density gradient centrifugation of the plasma membrane fraction prepared from Arabidopsis seedlings after treatment with 1% (w/v) Triton X-100. When separated with SDS-PAGE and 2D SDS-PAGE for differential protein expression analysis, DRM-associated proteins showed quantitative changes during cold acclimation, suggesting the involvement of DRM in cold acclimation in plants. We are now identifying cold-responsive DRM-associated proteins by MALDI-TOF-MS.
