Abstract
Arabidopsis thaliana increases freezing tolerance upon exposure to low, non-freezing temperatures, which is known as cold acclimation. Cold acclimation results in substantial changes in protein composition and sphingolipids in the plasma membrane. In animal cells, it has been reported that sphingolipid-enriched membrane microdomains are isolated as low-density detergent-resistant plasma membrane (DRM) fraction and several DRM proteins play important roles in membrane trafficking and signal transduction. However, functions of the microdomains in plant cells are largely unknown. To investigate whether DRM proteins are associated with plant freezing tolerance, we compared DRM protein patterns during cold acclimation in Arabidopsis seedlings. When separated with SDS-PAGE and 2D-PAGE, there are quantitative changes in DRM during cold acclimation, suggesting a possible involvement in cold acclimation in Arabidopsis. We will present a progress of identification of cold-responsive DRM proteins using MALDI-TOF-MS and discuss the molecular aspect of the DRM proteins in plant cold acclimation.
