ALK4

ALK4 (also known as Activin receptor-like kinase 4) is a type of protein that in humans is encoded by the ACVR1B gene. It is a member of the serine/threonine protein kinase family and the TGF-beta receptor subfamily.

Function

ALK4 is a type 1 receptor for activin. 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 1 (this protein and ALK2) and two type 2 (ACVR2A and ACVR2B) receptors. This protein is a type 1 receptor which is essential for signaling.

Clinical significance

Mutations in the ALK4 gene are associated with several diseases, including pancreatic cancer and ovarian cancer. Inhibitors of ALK4 are being investigated as potential therapeutic agents for these and other conditions.

Structure

The structure of ALK4 is similar to that of other members of the TGF-beta receptor subfamily. It consists of a single-pass type I membrane protein with an extracellular region containing a cysteine-rich domain, a transmembrane domain, and a cytoplasmic domain with predicted serine/threonine specificity.

See also

• Activin
• TGF-beta receptor
• Serine/threonine protein kinase