ATP-dependent cell-free transfer of membrane lipids from nuclei to Golgi apparatus of germinating axes of garden pea

Summary ATP-dependent cell-free transfer of membrane constituents radiolabeled with ¹⁴C]acetate, primarily lipids, was demonstrated between isolated nuclei in suspension and purified Golgi apparatus immobilized on nitrocellulose strips prepared from garden pea (Pisum sativum) in the presence of pea cytosol. The ATP-dependent transfer correlated with the ability of the nuclear envelope to form 50–70 nm vesicles and blebs in an ATP-dependent manner. Specific transfer, transfer at 23°C minus transfer at 4°C, was approximately doubled by addition of ATP and was greater for peas germinated for 2 days than for peas germinated for 3 days. ATP plus cytosol-dependent transfer could not be demonstrated using radiolabeled pea nuclei as donor with purified endoplasmic reticulum, plasma membrane, nuclei, mitochondria or amyloplasts as acceptors. The results provide a second example, in addition to transfer between endoplasmic reticulum and Golgi apparatus, where ATP-and temperature-dependent transfer via 50–70 nm transition vesicles can be demonstrated in a cell-free system.