PROSITE documentation PDOC00188
Cytosolic fatty-acid binding proteins signature


A number of low molecular weight proteins which bind fatty acids and other organic anions are present in the cytosol [1,2]. Most of them are structurally related and have probably diverged from a common ancestor. This structure is a ten stranded antiparallel β-barrel, albeit with a wide discontinuity between the fourth and fifth strands, with a repeated + 1 topology enclosing a internal ligand binding site [2,7]. Proteins known to belong to this family include:

  • Six, tissue-specific, types of fatty acid binding proteins (FABPs) found in liver, intestine, heart, epidermal, adipocyte, brain/retina. Heart FABP is also known as mammary-derived growth inhibitor (MDGI), a protein that reversibly inhibits proliferation of mammary carcinoma cells. Epidermal FABP is also known as psoriasis-associated FABP [3].
  • Insect muscle fatty acid-binding proteins.
  • Testis lipid binding protein (TLBP).
  • Cellular retinol-binding proteins I and II (CRBP).
  • Cellular retinoic acid-binding protein (CRABP).
  • Gastrotropin, an ileal protein which stimulates gastric acid and pepsinogen secretion. It seems that gastrotropin binds to bile salts and bilirubins.
  • Fatty acid binding proteins MFB1 and MFB2 from the midgut of the insect Manduca sexta [4].

In addition to the above cytosolic proteins, this family also includes:

  • Myelin P2 protein, which may be a lipid transport protein in Schwann cells. P2 is associated with the lipid bilayer of myelin.
  • Schistosoma mansoni protein Sm14 [5] which seems to be involved in the transport of fatty acids.
  • Ascaris suum p18 a secreted protein that may play a role in sequestering potentially toxic fatty acids and their peroxidation products or that may be involved in the maintenance of the impermeable lipid layer of the eggshell.
  • Hypothetical fatty acid-binding proteins F40F4.2, F40F4.3, F40F4.4 and ZK742.5 from Caenorhabditis elegans.

We use as a signature pattern for these proteins a segment from the N-terminal extremity.


It is suggested, on the basis of similarities of structure, function, and sequence, that this family forms an overall superfamily, called the calycins, with the lipocalin <PDOC00187> and avidin/streptavidin <PDOC00499> families [6,7].

Expert(s) to contact by email:

Flower D.R.

Last update:

April 2006 / Pattern revised.


Technical section

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

FABP, PS00214; Cytosolic fatty-acid binding proteins signature  (PATTERN)


1AuthorsBernier I. Jolles P.
TitleA survey on cytosolic non-enzymic proteins involved in the metabolism of lipophilic compounds: from organic anion binders to new protein families.
SourceBiochimie 69:1127-1152(1987).
PubMed ID3129018

2AuthorsVeerkamp J.H. Peeters R.A. Maatman R.G.H.J.
TitleStructural and functional features of different types of cytoplasmic fatty acid-binding proteins.
SourceBiochim. Biophys. Acta 1081:1-24(1991).
PubMed ID8068722

3AuthorsSiegenthaler G. Hotz R. Chatellard-Gruaz D. Didierjean L. Hellman U. Saurat J.-H.
TitlePurification and characterization of the human epidermal fatty acid-binding protein: localization during epidermal cell differentiation in vivo and in vitro.
SourceBiochem. J. 302:363-371(1994).
PubMed ID8092987

4AuthorsSmith A.F. Tsuchida K. Hanneman E. Suzuki T.C. Wells M.A.
TitleIsolation, characterization, and cDNA sequence of two fatty acid-binding proteins from the midgut of Manduca sexta larvae.
SourceJ. Biol. Chem. 267:380-384(1992).
PubMed ID1730603

5AuthorsMoser D. Tendler M. Griffiths G. Klinkert M.-Q.
TitleA 14-kDa Schistosoma mansoni polypeptide is homologous to a gene family of fatty acid binding proteins.
SourceJ. Biol. Chem. 266:8447-8454(1991).
PubMed ID2022660

6AuthorsFlower D.R. North A.C.T. Attwood T.K.
TitleStructure and sequence relationships in the lipocalins and related proteins.
SourceProtein Sci. 2:753-761(1993).
PubMed ID7684291

7AuthorsFlower D.R.
TitleStructural relationship of streptavidin to the calycin protein superfamily.
SourceFEBS Lett. 333:99-102(1993).
PubMed ID8224179

PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)