Tags: Protein.
SAR1A or Sar1 is a protein involved in membrane trafficking. It is a GTPase found in COPII vesicles. It regulates the assembly and disassembly of COPII coats.GDP-bound Sar1 interacts with the membrane-bound exchange factor Sec12 and exchanges its bound GDP for GTP. The hydrophobic N-terminus of Sar1-GTP then locates it to the membrane where it serves as the binding site for the Sec23/Sec24 protein coat complex.