15. 植物細胞膜マイクロドメインタンパク質の低温応答性(平成20年度第54回低温生物工学会年会)

概要

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Arabidopsis thaliana increases freezing tolerance upon exposure to low, non-freezing temperatures, which is known as cold acclimation (CA). CA results in significant changes in the lipid and protein compositions in the plasma membrane and these changes affect the freezing tolerance of plants. Recently, domains in the plasma membrane (called as microdomains), which contain membrane specific proteins associated with membrane trafficking and signal transduction, are isolated as detergent-resistant plasma membrane fractions (DRM). To investigate the role of DRM-associated proteins in CA, we characterized cold-responsive DRM-associated proteins in Arabidopsis seedlings during CA. Two-dimensional differential gel electrophoresis and subsequent mass spectrometric analyses revealed that many proteins quantitatively changed during CA, among which P-type H^+-ATPase, aquaporin and endocytosis-related proteins increased and tubulin, actin and V-type H^+-ATPase subunits decreased in DRM. Gene expression analysis indicated that the protein accumulation levels in DRM during CA were not regulated at levels of transcription. These results suggest that (1) Arabidopsis plasma membrane microdomains play a role as a platform for membrane transport, membrane trafficking and cytoskeleton interaction and (2) the changes in these proteins are not correlated with the changes in gene expression levels during CA.
2008-12-30