A number of molecular events occur during the initiation of vesicle budding at the ER membrane. Please put these in order. (The 1st-6th choices are randomly shuffled, so please choose the accurate one.) 1. Sar1-GTPase becomes active, inserts into the ER membrane, and begins recruiting adaptor, receptor, and coat proteins. 2. The naked transport vesicle fuses to the next membrane with the help of SNARE proteins.
3. Sar1-GTPase undergoes hydrolysis in which GTP chemically converts to GDP.
4. Sar1-GTPase is now inactive, allowing it and coat proteins to fall off of the membrane.
5. Sar1-GEF at the ER membrane helps Sar1- GTPase exchange a GDP molecule out and a GTP molecule in.
6. COPII assembly helps bud a vesicle off of the ER membrane.