VAP protein family

VAP proteins are conserved integral membrane proteins of the endoplasmic reticulum found in all eukaryotic cells.^[1] VAP stands for VAMP-associated protein,^[2] where VAMP stands for vesicle-associated membrane protein. Humans have two VAPs that consist of the essential Major Sperm Protein domain and linker plus transmembrane helix to attach to the ER: VAPA and VAPB.^[3] A third VAP-like protein is Motile sperm domain containing 2 (MOSPD2), which has all the elements of VAP, and like them binds FFAT motifs, but has at its N-terminus a CRAL-TRIO domain that can bind and transfer lipids.^[4]

VAMP-associated membrane protein
Identifiers
Symbol	VAP
InterPro	IPR016763
Membranome	202

VAP includes the whole family of protein homologues in all species. For example, baker's yeast expresses two VAPs: Scs2 and Scs22.^[5][6]

References

1. Weir ML, Klip A, Trimble WS (July 1998). "Identification of a human homologue of the vesicle-associated membrane protein (VAMP)-associated protein of 33 kDa (VAP-33): a broadly expressed protein that binds to VAMP". The Biochemical Journal. 333 (2): 247–51. doi:10.1042/bj3330247. PMC 1219579. PMID 9657962.
2. Skehel PA, Martin KC, Kandel ER, Bartsch D (September 1995). "A VAMP-binding protein from Aplysia required for neurotransmitter release". Science. 269 (5230): 1580–3. Bibcode:1995Sci...269.1580S. doi:10.1126/science.7667638. PMID 7667638.
3. Nishimura Y, Hayashi M, Inada H, Tanaka T (January 1999). "Molecular cloning and characterization of mammalian homologues of vesicle-associated membrane protein-associated (VAMP-associated) proteins". Biochemical and Biophysical Research Communications. 254 (1): 21–6. doi:10.1006/bbrc.1998.9876. PMID 9920726.
4. Di Mattia, Thomas; Wilhelm, Léa P.; Ikhlef, Souade; Wendling, Corinne; Spehner, Danièle; Nominé, Yves; Giordano, Francesca; Mathelin, Carole; Drin, Guillaume; Tomasetto, Catherine; Alpy, Fabien (July 2018). "Identification of MOSPD2, a novel scaffold for endoplasmic reticulum membrane contact sites". EMBO Reports. 19 (7). doi:10.15252/embr.201745453. ISSN 1469-3178. PMC 6030701. PMID 29858488.
5. Nikawa J, Murakami A, Esumi E, Hosaka K (July 1995). "Cloning and sequence of the SCS2 gene, which can suppress the defect of INO1 expression in an inositol auxotrophic mutant of Saccharomyces cerevisiae". Journal of Biochemistry. 118 (1): 39–45. doi:10.1093/oxfordjournals.jbchem.a124889. PMID 8537323.
6. Loewen CJ, Levine TP (April 2005). "A highly conserved binding site in vesicle-associated membrane protein-associated protein (VAP) for the FFAT motif of lipid-binding proteins". The Journal of Biological Chemistry. 280 (14): 14097–104. doi:10.1074/jbc.M500147200. PMID 15668246.