Exocytosis Movie 2
ER-to-Golgi transport using the viral glycoprotein ts045 VSVG tagged with green fluorescent protein (VSVG-GFP).
Upon export from the ER, VSVG-GFP became concentrated in many differently shaped, rapidly forming pre-Golgi structures, which translocated inwards towards the Golgi complex along microtubules by using the microtubule minus-end-directed motor complex of dynein/dynactin.
No loss of fluorescent material from pre-Golgi structures occurred during their translocation to the Golgi complex and they frequently stretched into tubular shapes.
Paper results indicate that these pre-Golgi carrier structures moving unidirectionally along microtubule tracks are responsible for transporting VSVG-GFP through the cytoplasm to the Golgi complex.
This contrasts with the traditional focus on small vesicles as the primary vehicles for ER-to-Golgi transport.
VSVG protein from the ts045 mutant strain of vesicular stomatitis virus has been widely used to study membrane transport because of its reversible misfolding and retention in the ER at 40 °C and its ability to move out of the ER and into the Golgi complex upon temperature reduction to 32 °C
(text modified from article)
Reprinted by permission from Macmillan Publishers Ltd: Nature ( ER-to-Golgi transport visualized in living cells Nature: 1997, 389(6646);81-5), copyright (1997)
Dr Mark Hill 2015, UNSW Cell Biology - UNSW CRICOS Provider Code No. 00098G