Lipid-transfer proteins: Tools for manipulating membrane lipids

Like other eukaryotic cells, plant cells contain proteins able to bind or to transfer lipids. Since they are able to facilitate movements of various phospholipids between membranes and are also capable of binding fatty acids or acyl-CoAs, they have been termed lipid-transfer proteins (LTP). LTPs are basic proteins containing 90 to 95 residues (molecular mass 9 kDa), eight of them being cysteines found in conserved locations. These proteins have been used to manipulate in vitro the lipid composition of isolated membranes either from plant or mammalian sources. In addition to purified LTPs, recombinant LTPs produced by genes expressed in microorganisms can be used for this purpose. Several genes coding for these proteins have been characterized in various plants with different patterns of expression. However, it remains to be investigated whether these recombinant proteins behave functionally as LTPs. The use of purified or recombinant LTPs is promising for the study of the effect of lipid composition on membrane functional properties.