Transported first from ER to cis-Golgi network to trans-Golgi network. Using cisternal transportation.
When it reaches the trans-Golgi network, proteins are further sorted into either plasma membrane
types or lysosomes.
Three Types of Vesicles exist. Clathrin, COPII (ER to Golgi), and COPI (Golgi to ER). Different vesicles have
different coat proteins. COPII has 4 types of Sec proteins. COPI has 2 types of proteins. COPII has a GDP
binding protein called Sar 1. These coat proteins serve two functions, first help in the formation of the
vesicle, shape and assemble the vesicle into the correct shape, secondly it allows for the vesicles to
select the type of cargoes the vesicles will carry.
COPII: SarI. COPI: Arf I. Clathrin: Arf6. These 3 proteins are used in the formation of vesicles, they are
called small-GTP binding proteins. GAP and GEF act as the offstream regulators to the GTP/GDP bound
Sec12, is a special GEF that recruit and activate Sar1. This will expose the hydrophobic N-terminal helix
of Sar1, which is then inserted into the ER. Sar1-GTP then recruit sec2