In molecular biology, the CFC domain (Cripto_Frl-1_Cryptic domain) is a protein domain found at the C-terminus of a number of proteins including Cripto

Cripto

Cryptic family protein 1B is a protein that in humans is encoded by the CFC1B gene. Cryptic family protein 1B acts as a receptor for the TGF beta signaling pathway....

 (or teratocarcinoma-derived growth

Cell growth

The term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...

 factor). It is structurally similar to the C-terminal extracellular

Extracellular

In cell biology, molecular biology and related fields, the word extracellular means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid...

 portions of Jagged 1 and Jagged 2

JAG2

Protein jagged-2 is a protein that in humans is encoded by the JAG2 gene.-Further reading:...

. CFC is approx 40-residues long, compacted by three internal disulphide bridges, and binds Alk4

ACVR1B

Activin receptor type-1B is a protein that in humans is encoded by the ACVR1B gene.ACVR1B or ALK-4 acts as a transducer of activin or activin like ligands signals. Activin binds to either ACVR2A or ACVR2B and then forms a complex with ACVR1B. These go on to recruit the R-SMADs SMAD2 or SMAD3...

 via a hydrophobic patch. CFC is structurally homologous

Homology (biology)

Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 to the VWFC-like domain.

The CFC domain appears to play a crucial role in the tumourigenic activity of Cripto proteins, as it is through the CFC domain that Cripto interferes with the onco-suppressive activity of Activins, either by blocking the Activin receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

 ALK4 or by antagonising proteins

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 of the TGF-beta family.