4fao

Structural highlights

Disease

[AVR2B_HUMAN] Defects in ACVR2B are the cause of visceral heterotaxy autosomal type 4 (HTX4) [MIM:613751]. A form of visceral heterotaxy, a complex disorder due to disruption of the normal left-right asymmetry of the thoracoabdominal organs. It results in an abnormal arrangement of visceral organs, and a wide variety of congenital defects. Clinical features of visceral heterotaxy type 4 include dextrocardia, right aortic arch and a right-sided spleen, anomalies of the inferior and the superior vena cava, atrial ventricular canal defect with dextro-transposed great arteries, pulmonary stenosis, polysplenia and midline liver.^[1] [ACVL1_HUMAN] Defects in ACVRL1 are the cause of hereditary hemorrhagic telangiectasia type 2 (HHT2) [MIM:600376]; also known as Osler-Rendu-Weber syndrome 2 (ORW2). HHT2 is an autosomal dominant multisystemic vascular dysplasia, characterized by recurrent epistaxis, muco-cutaneous telangiectases, gastro-intestinal hemorrhage, and pulmonary, cerebral and hepatic arteriovenous malformations; all secondary manifestations of the underlying vascular dysplasia.^{[2] [3] [4] [5] [6] [7] [8] [9] [10]}

Function

[GDF2_HUMAN] Potent circulating inhibitor of angiogenesis. Could be involved in bone formation. Signals through the type I activin receptor ACVRL1 but not other Alks.^{[11] [12]} [AVR2B_HUMAN] Transmembrane serine/threonine kinase activin type-2 receptor forming an activin receptor complex with activin type-1 serine/threonine kinase receptors (ACVR1, ACVR1B or ACVR1c). Transduces the activin signal from the cell surface to the cytoplasm and is thus regulating many physiological and pathological processes including neuronal differentiation and neuronal survival, hair follicle development and cycling, FSH production by the pituitary gland, wound healing, extracellular matrix production, immunosuppression and carcinogenesis. Activin is also thought to have a paracrine or autocrine role in follicular development in the ovary. Within the receptor complex, the type-2 receptors act as a primary activin receptors (binds activin-A/INHBA, activin-B/INHBB as well as inhibin-A/INHA-INHBA). The type-1 receptors like ACVR1B act as downstream transducers of activin signals. Activin binds to type-2 receptor at the plasma membrane and activates its serine-threonine kinase. The activated receptor type-2 then phosphorylates and activates the type-1 receptor. Once activated, the type-1 receptor binds and phosphorylates the SMAD proteins SMAD2 and SMAD3, on serine residues of the C-terminal tail. Soon after their association with the activin receptor and subsequent phosphorylation, SMAD2 and SMAD3 are released into the cytoplasm where they interact with the common partner SMAD4. This SMAD complex translocates into the nucleus where it mediates activin-induced transcription. Inhibitory SMAD7, which is recruited to ACVR1B through FKBP1A, can prevent the association of SMAD2 and SMAD3 with the activin receptor complex, thereby blocking the activin signal. Activin signal transduction is also antagonized by the binding to the receptor of inhibin-B via the IGSF1 inhibin coreceptor.^[13] [ACVL1_HUMAN] Type I receptor for TGF-beta family ligands BMP9/GDF2 and BMP10 and important regulator of normal blood vessel development. On ligand binding, forms a receptor complex consisting of two type II and two type I transmembrane serine/threonine kinases. Type II receptors phosphorylate and activate type I receptors which autophosphorylate, then bind and activate SMAD transcriptional regulators. May bind activin as well.^{[14] [15]}

See Also

• Growth differentiation factor

References

1. ↑ Kosaki R, Gebbia M, Kosaki K, Lewin M, Bowers P, Towbin JA, Casey B. Left-right axis malformations associated with mutations in ACVR2B, the gene for human activin receptor type IIB. Am J Med Genet. 1999 Jan 1;82(1):70-6. PMID:9916847
2. ↑ Berg JN, Gallione CJ, Stenzel TT, Johnson DW, Allen WP, Schwartz CE, Jackson CE, Porteous ME, Marchuk DA. The activin receptor-like kinase 1 gene: genomic structure and mutations in hereditary hemorrhagic telangiectasia type 2. Am J Hum Genet. 1997 Jul;61(1):60-7. PMID:9245985 doi:S0002-9297(07)64277-3
3. ↑ Johnson DW, Berg JN, Baldwin MA, Gallione CJ, Marondel I, Yoon SJ, Stenzel TT, Speer M, Pericak-Vance MA, Diamond A, Guttmacher AE, Jackson CE, Attisano L, Kucherlapati R, Porteous ME, Marchuk DA. Mutations in the activin receptor-like kinase 1 gene in hereditary haemorrhagic telangiectasia type 2. Nat Genet. 1996 Jun;13(2):189-95. PMID:8640225 doi:10.1038/ng0696-189
4. ↑ Klaus DJ, Gallione CJ, Anthony K, Yeh EY, Yu J, Lux A, Johnson DW, Marchuk DA. Novel missense and frameshift mutations in the activin receptor-like kinase-1 gene in hereditary hemorrhagic telangiectasia. Mutations in brief no. 164. Online. Hum Mutat. 1998;12(2):137. PMID:10694922 doi:<137::AID-HUMU16>3.0.CO;2-J 10.1002/(SICI)1098-1004(1998)12:2<137::AID-HUMU16>3.0.CO;2-J
5. ↑ Abdalla SA, Pece-Barbara N, Vera S, Tapia E, Paez E, Bernabeu C, Letarte M. Analysis of ALK-1 and endoglin in newborns from families with hereditary hemorrhagic telangiectasia type 2. Hum Mol Genet. 2000 May 1;9(8):1227-37. PMID:10767348
6. ↑ Kjeldsen AD, Brusgaard K, Poulsen L, Kruse T, Rasmussen K, Green A, Vase P. Mutations in the ALK-1 gene and the phenotype of hereditary hemorrhagic telangiectasia in two large Danish families. Am J Med Genet. 2001 Feb 1;98(4):298-302. PMID:11170071
7. ↑ Trembath RC, Thomson JR, Machado RD, Morgan NV, Atkinson C, Winship I, Simonneau G, Galie N, Loyd JE, Humbert M, Nichols WC, Morrell NW, Berg J, Manes A, McGaughran J, Pauciulo M, Wheeler L. Clinical and molecular genetic features of pulmonary hypertension in patients with hereditary hemorrhagic telangiectasia. N Engl J Med. 2001 Aug 2;345(5):325-34. PMID:11484689 doi:10.1056/NEJM200108023450503
8. ↑ Harrison RE, Flanagan JA, Sankelo M, Abdalla SA, Rowell J, Machado RD, Elliott CG, Robbins IM, Olschewski H, McLaughlin V, Gruenig E, Kermeen F, Halme M, Raisanen-Sokolowski A, Laitinen T, Morrell NW, Trembath RC. Molecular and functional analysis identifies ALK-1 as the predominant cause of pulmonary hypertension related to hereditary haemorrhagic telangiectasia. J Med Genet. 2003 Dec;40(12):865-71. PMID:14684682
9. ↑ Lesca G, Plauchu H, Coulet F, Lefebvre S, Plessis G, Odent S, Riviere S, Leheup B, Goizet C, Carette MF, Cordier JF, Pinson S, Soubrier F, Calender A, Giraud S. Molecular screening of ALK1/ACVRL1 and ENG genes in hereditary hemorrhagic telangiectasia in France. Hum Mutat. 2004 Apr;23(4):289-99. PMID:15024723 doi:10.1002/humu.20017
10. ↑ Kuehl HK, Caselitz M, Hasenkamp S, Wagner S, El-Harith el-HA, Manns MP, Stuhrmann M. Hepatic manifestation is associated with ALK1 in hereditary hemorrhagic telangiectasia: identification of five novel ALK1 and one novel ENG mutations. Hum Mutat. 2005 Mar;25(3):320. PMID:15712270 doi:10.1002/humu.9311
11. ↑ David L, Mallet C, Keramidas M, Lamande N, Gasc JM, Dupuis-Girod S, Plauchu H, Feige JJ, Bailly S. Bone morphogenetic protein-9 is a circulating vascular quiescence factor. Circ Res. 2008 Apr 25;102(8):914-22. doi: 10.1161/CIRCRESAHA.107.165530. Epub, 2008 Feb 28. PMID:18309101 doi:10.1161/CIRCRESAHA.107.165530
12. ↑ Mahlawat P, Ilangovan U, Biswas T, Sun LZ, Hinck AP. Structure of the Alk1 extracellular domain and characterization of its bone morphogenetic protein (BMP) binding properties. Biochemistry. 2012 Aug 14;51(32):6328-41. Epub 2012 Aug 2. PMID:22799562 doi:10.1021/bi300942x
13. ↑ Attisano L, Wrana JL, Montalvo E, Massague J. Activation of signalling by the activin receptor complex. Mol Cell Biol. 1996 Mar;16(3):1066-73. PMID:8622651
14. ↑ Mahlawat P, Ilangovan U, Biswas T, Sun LZ, Hinck AP. Structure of the Alk1 extracellular domain and characterization of its bone morphogenetic protein (BMP) binding properties. Biochemistry. 2012 Aug 14;51(32):6328-41. Epub 2012 Aug 2. PMID:22799562 doi:10.1021/bi300942x
15. ↑ Townson SA, Martinez-Hackert E, Greppi C, Lowden P, Sako D, Liu J, Ucran JA, Liharska K, Underwood KW, Seehra J, Kumar R, Grinberg AV. Specificity and structure of a high affinity activin receptor-like kinase 1 (ALK1) signaling complex. J Biol Chem. 2012 Jun 20. PMID:22718755 doi:10.1074/jbc.M112.377960
16. ↑ Townson SA, Martinez-Hackert E, Greppi C, Lowden P, Sako D, Liu J, Ucran JA, Liharska K, Underwood KW, Seehra J, Kumar R, Grinberg AV. Specificity and structure of a high affinity activin receptor-like kinase 1 (ALK1) signaling complex. J Biol Chem. 2012 Jun 20. PMID:22718755 doi:10.1074/jbc.M112.377960