SEC23 Homolog A (SEC23A)

SEC23Ais a member of the SEC23 subfamily of the SEC23/SEC24 family. It is part of a protein complex and found in the ribosome-free transitional face of the endoplasmic reticulum (ER) and associated vesicles. This protein has similarity to yeast Sec23p component of COPII. COPII is the coat protein complex responsible for vesicle budding from the ER. The encoded protein is suggested to play a role in the ER-Golgi protein trafficking.The deduced 765-amino acid protein shares 47.3% identity with yeast Sec23 and 84.3% identity with human SEC23B. RNase protection assays detected variable levels of SEC23A in all human tissues and cell lines examined. Western blot analysis revealed an 85-kD SEC23A protein in HepG2 cells and in mouse and rat tissues. SEC23A partitioned equally between cytosol and membranes in HepG2 cells.