Activin receptor type-1B is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''ACVR1B''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. ACVR1B or ALK-4 acts as a transducer of activin or activin-like ligands (e.g.,

inhibin Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual ...

) signals. Activin binds to either

ACVR2A Activin receptor type-2A is a protein that in humans is encoded by the ''ACVR2A'' gene. ACVR2A is an activin type 2 receptor. Function This gene encodes activin A type II receptor. Activins are dimeric growth and differentiation factors which ...

ACVR2B Activin receptor type-2B is a protein that in humans is encoded by the ''ACVR2B'' gene. ACVR2B is an activin type 2 receptor. Function Activins are dimeric growth and differentiation factors which belong to the transforming growth factor-bet ...

and then forms a complex with ACVR1B. These go on to recruit the R-SMADs

SMAD2 Mothers against decapentaplegic homolog 2 also known as SMAD family member 2 or SMAD2 is a protein that in humans is encoded by the ''SMAD2'' gene. MAD homolog 2 belongs to the SMAD, a family of proteins similar to the gene products of the ''Dros ...

SMAD3 Mothers against decapentaplegic homolog 3 also known as SMAD family member 3 or SMAD3 is a protein that in humans is encoded by the SMAD3 gene. SMAD3 is a member of the SMAD family of proteins. It acts as a mediator of the signals initiated by t ...

. ACVR1B also transduces signals of

nodal Nodal homolog is a secretory protein that in humans is encoded by the ''NODAL'' gene which is located on chromosome 10q22.1. It belongs to the transforming growth factor beta superfamily (TGF-β superfamily). Like many other members of this superf ...

, GDF-1, and Vg1; however, unlike activin, they require other coreceptor molecules such as the protein

Cripto Cripto is an EGF-CFC or epidermal growth factor-CFC, which is encoded by the Cryptic family 1 gene. 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 be ...

Function

Activins are dimeric growth and differentiation factors which belong to the transforming growth factor-beta (TGF-beta) superfamily of structurally related signaling proteins. Activins signal through a heteromeric complex of receptor serine kinases which include at least two type I (I and IB) and two type II (II and IIB) receptors. These receptors are all transmembrane proteins, composed of a ligand-binding extracellular domain with a cysteine-rich region, a transmembrane domain, and a cytoplasmic domain with predicted serine/threonine specificity. Type I receptors are essential for signaling, and type II receptors are required for binding ligands and for expression of type I receptors. Type I and II receptors form a stable complex after ligand binding, resulting in phosphorylation of type I receptors by type II receptors. This gene encodes activin A type IB receptor, composed of 11 exons. Alternative splicing and alternative polyadenylation result in 3 fully described transcript variants. The mRNA expression of variants 1, 2, and 3 is confirmed, and a potential fourth variant contains an alternative exon 8 and lacks exons 9 through 11, but its mRNA expression has not been confirmed.

Interactions

ACVR1B has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with *

, and

Function

Interactions

References

External links

Further reading