De novo-designed peptide transforms Golgi-specific lipids into Golgi-like nanotubules.

Cellular organelles, such as the Golgi apparatus and the endoplasmic reticu lum, adopt characteristic structures depending on their function. While the tubular shapes of these structures result from complex protein-lipid inter actions that are not fully understood, some fundamental machinery must be r equired. We show here that a de novo-designed 18-mer amphipathic a-helical peptide, Hel 13-5, transforms spherical liposomes made from a Golgi-specifi c phospholipid mixture into nanotubules on the scale of and resembling the shape of the nanotubules that form the Golgi apparatus. Furthermore, we sho w that that the size and the shape of such nanotubules depend on lipid comp osition and peptide properties such as length and the ratio of hydrophobic to hydrophilic amino acids. Although the question of precisely how nature e ngineers organellar membranes remains unknown, our simple novel system prov ides a basic set of tools to begin addressing this question.