Abstract
Glycerolipids are major components of membrane-lipids. Although glycerolipids can solely form lipid bilayer membrane, other type lipids, sterols and sphingolipids, also exist in cellular membrane. These lipid diversities are considered to be important for the function of cellular membrane. We have shown the developmental function of sterols by molecular genetics. So what is the function of sterols for the membrane lipids environment? We here report that the potential regulatory mechanisms of plastidial lipids from the analyses of sterol and glycerolipids profiles of sterol biosynthetic mutants.
LC-MS analyses demonstrated no difference of phospholipids profile on 19 mutants of sterol biosynthetic pathway. Although phospholipids as well as sterols are components of cellular membrane, alteration of sterol profile did not affect phospholipids profile. On the contrary, the profile of galactolipids, major components of plastidial lipids, was altered in the mutant of HMGR, the key enzyme of the sterol biosynthesis. Since the level of plastidial phospholipids was not affected in this mutant, HMGR may contribute to the regulatory mechanisms of the galactolipids biosynthesis in plastids.
