Cryptic family protein 1B is a protein

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...

 that in humans is encoded by the CFC1B gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. Cryptic family protein 1B acts as a receptor for the TGF beta signaling pathway

TGF beta signaling pathway

The Transforming growth factor beta signaling pathway is involved in many cellular processes in both the adult organism and the developing embryo including cell growth, cell differentiation, apoptosis, cellular homeostasis and other cellular functions. In spite of the wide range of cellular...

.

Cryptic is a glycosylphosphatidylinositol-anchored coreceptor that binds nodal

NODAL

Nodal is a protein that in humans is encoded by the NODAL gene. It is a member of the TGF beta superfamily. Like many other members of this superfamily, it is involved in cell differentiation...

 and the activin type I (ALK)-4 receptor (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...

).

Structure

Cripto is composed of two adjacent cysteine

Cysteine

Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...

-rich motifs, the EGF-like and the CFC

CFC domain

In molecular biology, the CFC domain is a protein domain found at the C-terminus of a number of proteins including Cripto . It is structurally similar to the C-terminal extracellular portions of Jagged 1 and Jagged 2...

, of a N-terminal signal peptide and of a C-terminal hydrophobic region attached by a GPI anchor.

NMR data confirm that the CFC domain has a C1-C4, C2-C6, C3-C5 disulfide pattern and show that structures are rather flexible and globally extended, with three noncanonical antiparallel strands.

Clinical significance

CFC1B has oncogene

Oncogene

An oncogene is a gene that has the potential to cause cancer. In tumor cells, they are often mutated or expressed at high levels.An oncogene is a gene found in the chromosomes of tumor cells whose activation is associated with the initial and continuing conversion of normal cells into cancer...

 potential. Furthermore the cryptic protein is highly overexpressed in many tumors.

Cripto is one of the key regulators of embryonic stem cells differentiation into cardiomyocyte

Cardiac muscle

Cardiac muscle is a type of involuntary striated muscle found in the walls and histologic foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle...

 vs neuronal fate.