VAD1 analog of StAR-related lipid transfer (VASt) is a steroidogenic acute regulatory protein‐related lipid transfer (StART)-like lipid-binding domain first identified in the vad1 (vascular associated death1) protein in Arabidopsis thaliana (mouse-ear cress ).
[1][3] While VASt is a member of the Bet v1-like superfamily, it is unclear if it evolved from the same ancestral domain as the START domain or is an example of convergent evolution.
[1] The domain is highly conserved across all eukaryotes and is typically present in only one copy in VASt domain-containing proteins.
The pocket formed is large enough to bind one lipid such as cholesterol,[4] 25-hydroxycholesterol[5] or ergosterol.
[2][3] Analysis of the crystal structure of unbound and bound forms of VASt domains in lipid transfer proteins anchored at a membrane contact site (LAMs) from yeast revealed that the domain contains an accessible hydrophobic cavity.