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
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 .
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 .
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  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
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
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>
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