1. Analogs of the Golgi complex in microsporidia: Structure and avesicular mechanisms of function
- Author
-
Yuliya Y. Sokolova, Maria Antonietta De Matteis, Alberto Luini, Peter Auinger, Daniele Di Giandomenico, Alexander A. Mironov, Alvar Trucco, Viacheslav V. Dolgikh, Yuri S. Tokarev, P. B. Semenov, Sergei Skarlato, Igor V. Senderskiy, Margit Pavelka, Galina V. Beznoussenko, Massimo Micaroni, Elena V. Seliverstova, E. S. Snigirevskaya, Yan Yu. Komissarchik, Beznoussenko, Galina V., Dolgikh, Viacheslav V., Seliverstova, Elena V., Semenov, Petr B., Tokarev, Yuri S., Trucco, Alvar, Micaroni, Massimo, Di Giandomenico, Daniele, Auinger, Peter, Senderskly, Igor V., Skarlato, Sergei O., Snigirevskaya, Ekaterina S., Komissarchik, Yan Y. u., Pavelka, Margit, DE MATTEIS, Maria Antonietta, Luini, Alberto, Sokolova, Yuliya Y. a., and Mironov, Alexander A.
- Subjects
Fat Body ,Golgi Apparatus ,Golgi Apparatu ,Biology ,Endoplasmic Reticulum ,Gryllidae ,symbols.namesake ,Imaging, Three-Dimensional ,Species Specificity ,Microsporidiosis ,Golgi ,Image Processing, Computer-Assisted ,Animals ,Microsporidiosi ,Secretory pathway ,Life Cycle Stages ,Host cell cytosol ,Animal ,Endoplasmic reticulum ,Vesicle ,fungi ,Cell Membrane ,Cell Biology ,COP-Coated Vesicles ,Golgi apparatus ,COP-I vesicle ,Cell biology ,Life Cycle Stage ,Secretory protein ,Microsporidia ,Polar tube ,symbols ,Intracellular transport ,COP-Coated Vesicle - Abstract
Microsporidia are obligatory intracellular parasites, most species of which live in the host cell cytosol. They synthesize and then transport secretory proteins from the endoplasmic reticulum to the plasma membrane for formation of the spore wall and the polar tube for cell invasion. However, microsporidia do not have a typical Golgi complex. Here, using quick-freezing cryosubstitution and chemical fixation, we demonstrate that the Golgi analogs of the microsporidia Paranosema (Antonospora) grylli and Paranosema locustae appear as 300-nm networks of thin (25- to 40-nm diameter), branching or varicose tubules that display histochemical features of a Golgi, but that do not have vesicles. Vesicles are not formed even if membrane fusion is inhibited. These tubular networks are connected to the endoplasmic reticulum, the plasma membrane and the forming polar tube, and are positive for Sec13, γCOP and analogs of giantin and GM130. The spore-wall and polar-tube proteins are transported from the endoplasmic reticulum to the target membranes through these tubular networks, within which they undergo concentration and glycosylation. We suggest that the intracellular transport of secreted proteins in microsporidia occurs by a progression mechanism that does not involve the participation of vesicles generated by coat proteins I and II.
- Published
- 2007