TY - JOUR
T1 - Analogs of the Golgi complex in microsporidia
T2 - Structure and avesicular mechanisms of function
AU - Beznoussenko, Galina V.
AU - Dolgikh, Viacheslav V.
AU - Seliverstova, Elena V.
AU - Semenov, Petr B.
AU - Tokarev, Yuri S.
AU - Trucco, Alvar
AU - Micaroni, Massimo
AU - Di Giandomenico, Daniele
AU - Auinger, Peter
AU - Senderskly, Igor V.
AU - Skarlato, Sergei O.
AU - Snigirevskaya, Ekaterina S.
AU - Komissarchik, Yan Yu
AU - Pavelka, Margit
AU - De Matteis, Maria A.
AU - Luini, Alberto
AU - Sokolova, Yuliya Ya
AU - Mironov, Alexander A.
PY - 2007/4/1
Y1 - 2007/4/1
N2 - 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-mn 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.
AB - 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-mn 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.
KW - COP-I vesicles
KW - Golgi
KW - Intracellular transport
KW - Microsporidia
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U2 - 10.1242/jcs.03402
DO - 10.1242/jcs.03402
M3 - Article
C2 - 17356068
AN - SCOPUS:34248203076
VL - 120
SP - 1288
EP - 1298
JO - Journal of Cell Science
JF - Journal of Cell Science
SN - 0021-9533
IS - 7
ER -