VAP protein family

VAP proteins are conserved integral membrane proteins of the endoplasmic reticulum found in all eukaryotic cells.

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] VAP includes the whole family of protein homologues in all species.

For example, baker's yeast expresses two VAPs: Scs2 and Scs22.