Structure and dynamics of the Golgi complex at 15 degrees C: low temperature induces the formation of Golgi-derived tubules.
Immunofluorescence and cryoimmunoelectron microscopy were used to examine the morphologic and functional effects on the Golgi complex when protein transport is blocked at the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) in HeLa cells incubated at low temperature (15 degrees C). At this temperature, the Golgi complex showed long tubules containing resident glycosylation enzymes but not matrix proteins. These Golgi-derived tubules also lacked anterograde (VSV-G) or retrograde (Shiga toxin) cargo. The formation of tubules was dependent on both energy and intact microtubule and actin cytoskeletons. Conversely, brefeldin A or cycloheximide treatments did not modify the appearance. When examined at the electron microscope, Golgi stacks were long and curved and appeared connected to tubules immunoreactive to galactosyltransferase antibodies but devoid of Golgi matrix proteins. Strikingly, COPI proteins moved from membranes to the cytosol at 15 degrees C, which could explain the formation of tubules.
Martínez-Alonso
Emma
E
Department of Cell Biology, School of Medicine, University of Murcia, 30100 Murcia, Spain.
Egea
Gustavo
G
Ballesta
José
J
Martínez-Menárguez
José A
JA
D020126:Brefeldin A / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D020755:Coat Protein Complex I / Q000378:metabolism; D005700:Galactosyltransferases / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D015739:Nocodazole / Q000494:pharmacology; D021381:Protein Transport; D013696:Temperature; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
D019086:Bridged Bicyclo Compounds, Heterocyclic; D020755:Coat Protein Complex I; D013844:Thiazoles; D053778:Thiazolidines; D020126:Brefeldin A; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase; C037068:latrunculin B; D015739:Nocodazole