Insights into the Golgi apparatus through unicellular algae

Abstract

Summary: The effects of brefeldin A(BFA)on the structure of the Golgi apparatus and the endoplasmic reticulum(ER)and on the thiamine pyrophosphatase activity in these organelles in two green algae, Scenedesmus acutus and Botryococcus braunii, were examined at various stages of the cell cycle, to obtain evidence for the existence of a retrograde transport from the Golgi bodies to the ER. The results demonstrated that a BFA-induced retrograde transport from the Golgi bodies to the ER occurred not only in mammalian cells but also in plant cells.In these two algae, the retrograde transport in the presence of BFA occurred in the interphase cells but not in dividing cells. We further investigated which cytoskeleton participated in this BFA-induced retrogradetransport in S. acutus. The results demonstrate that actin filaments directly mediate the BFA-induced retrograde transport of vesicles. This mechanism differs from that found in mammalian cells, in which microtubules mediate BFA-induced retrograde transport.