Abstract
Cold acclimation (CA) is associated with changes in lipid and protein compositions of the plasma membrane (PM), which is critical for the increase in freezing tolerance of plant cells. Recently, we demonstrated that CA dramatically changed composition of sphingolipid- and sterol-enriched PM microdomains, in which various functional protein complexes are localized to function efficiently (Minami et al., 2009). Proteomic and subsequent western blot analyses revealed that dynamin-related protein 1E (DRP1E), which is one of 16 Arabidopsis DRP family proteins, increased in PM microdomains after CA. DRP1E expression also increased after 12 hours of CA. With DRP1E::GFP-overexpressed Arabidopsis plants, DRP1E was demonstrated to be localized in/near the PM and the GFP signals came from the proximity of the PM non-uniformly. The capacity of CA was much less in the drp1e T-DNA insertion mutants than wild type. Because DRPs are thought to be associated with membrane trafficking and membrane fission processes, our results suggest that DRP1E contributes to freezing tolerance by helping reconstruction of the PM architecture through a vesicle-trafficking pathway in Arabidopsis during CA.
