Protein
Small COPII coat GTPase sar1
Organism
Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987)
Function
Small GTPase component of the coat protein complex II (COPII) which promotes the formation of transport vesicles from the endoplasmic reticulum (ER). The coat has two main functions, the physical deformation of the endoplasmic reticulum membrane into vesicles and the selection of cargo molecules. Vtr-7/sar1 controls the coat assembly in a stepwise manner. Activated sar1-GTP binds to membranes first and recruits the sec23/24 complex. These sec23/24-sar1 prebudding intermediates are then collected by the sec13/31 complex as subunits polymerize to form coated transport vesicles. Conversion to sar1-GDP triggers coat release and recycles COPII subunits (By similarity).
Similarity
Belongs to the small GTPase superfamily. SAR1 family.
Sequence
MWLWSWFYDILSNLGLLNKHGKLLFLGLDNAGKTTLLHMLKNDRVAILQPTLHPTSEELSVGNVKFTTFDLGGHQQARRLWKDYFPEVNGIVFLVDAKDHERLPEAKAEIDALLSMEELAKVPFVVLGNKIDHPEAVSEDELRQRLGLWQTTGKGRVPLEGIRPIEVFMCSVVMRQGYGEAIRWLSQYV