PROSITE documentation PDOC50191
CRAL-TRIO lipid binding domain profile


The CRAL-TRIO domain is a structurally conserved element of about 170 amino acids, which constitute a hydrophobic lipid binding pocket. The CRAL-TRIO domain is found in GTPase-activating proteins (GAPs), guanine nucleotide exchange factors (GEFs) and a family of hydrophobic ligand binding proteins, including the yeast SEC14 protein and mammalian retinaldehyde- and α-tocopherol-binding proteins. The CRAL-TRIO domain may either constitute all of the protein or only part of it [1,2,3,4,5].

The resolution of the crystal structure of SEC14 has revealed the structure of the CRAL-TRIO lipid binding domain (see <PDB:1AUA>). The CRAL-TRIO lipid binding domain is an α/β domain, which forms a large hydrophobic pocket. The pocket floor is constituted by six β-strands and the sides of the cavity are formed by α-helices [3].

Some proteins known to contain a CRAL-TRIO domain are listed below:

  • Yeast phosphatidylinositol-transfer protein (SEC14). It is required for transport of secretory proteins from the golgi complex in vivo and it catalyzes the transfer of phosphatidylinositol and phosphatidylcholine between membranes in vitro.
  • Animal retinal-binding protein.
  • Animal neurofibromin (protein NF-1). In human, defects in NF-1 are the cause of type 1 neurofibromatosis (NF-1), one of the most frequent autosomal dominant diseases.
  • Mammalian BCL2/adenovirus E1B 19 kDa protein-interacting protein 2 (NIP2). NIP2 is an apoptosis regulator.
  • Mammalian guanine nucleotide exchange factor DBS (DBL's big sister).
  • Mammalian cellular retinol retinaldehyde-binding protein (CRALBP). It carries 11-cis-retinol and 11-cis-retinaldehyde as endogenous ligands and may be a functional component of the visual cycle.
  • Mammalian α-tocopherol transfer protein (α-TTP). It binds α- tocopherol and enhances its transfer between separate membranes.
  • Mammalian α-tocopherol-associated protein (TAP).

The profile we developed covers the entire CRAL-TRIO domain.

Last update:

June 2002 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

CRAL_TRIO, PS50191; CRAL-TRIO lipid binding domain profile  (MATRIX)


1AuthorsSalama S.R. Cleves A.E. Malehorn D.E. Whitters E.A. Bankaitis V.A.
TitleCloning and characterization of Kluyveromyces lactis SEC14, a gene whose product stimulates Golgi secretory function in Saccharomyces cerevisiae.
SourceJ. Bacteriol. 172:4510-4521(1990).
PubMed ID2198263

2AuthorsSato Y. Arai H. Miyata A. Tokita S. Yamamoto K. Tanabe T. Inoue K.
TitlePrimary structure of alpha-tocopherol transfer protein from rat liver. Homology with cellular retinaldehyde-binding protein.
SourceJ. Biol. Chem. 268:17705-17710(1993).
PubMed ID8349655

3AuthorsSha B. Phillips S.E. Bankaitis V.A. Luo M.
TitleCrystal structure of the Saccharomyces cerevisiae phosphatidylinositol-transfer protein.
SourceNature 391:506-510(1998).
PubMed ID9461221

4AuthorsAravind L. Neuwald A.F. Ponting C.P.
TitleSec14p-like domains in NF1 and Dbl-like proteins indicate lipid regulation of Ras and Rho signaling.
SourceCurr. Biol. 9:R195-R197(1999).
PubMed ID10209105

5AuthorsZimmer S. Stocker A. Sarbolouki M.N. Spycher S.E. Sassoon J. Azzi A.
TitleA novel human tocopherol-associated protein: cloning, in vitro expression, and characterization.
SourceJ. Biol. Chem. 275:25672-25680(2000).
PubMed ID10829015

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