Fig.5.

Evolution of large lipid transfer proteins. Members of large lipid transfer proteins, such as MTP, apoB, and vitellogenin, share sequence homology. Sequence relationships depict a coevolution that correlates to the appearance of circulatory systems in insects and nematodes. Note that MTP is present in all organisms and is perhaps the first protein to evolve. Throughout evolution, different lipid carrier proteins have arisen, including vitellogenin, apolipophorin, and apoB. Approximate time of divergence is shown at break points. Modified from Ref. 71.