7sc4

Structural highlights

Disease

FLNA_HUMAN Defects in FLNA are the cause of periventricular nodular heterotopia type 1 (PVNH1) [MIM:300049; also called nodular heterotopia, bilateral periventricular (NHBP or BPNH). PVNH is a developmental disorder characterized by the presence of periventricular nodules of cerebral gray matter, resulting from a failure of neurons to migrate normally from the lateral ventricular proliferative zone, where they are formed, to the cerebral cortex. PVNH1 is an X-linked dominant form. Heterozygous females have normal intelligence but suffer from seizures and various manifestations outside the central nervous system, especially related to the vascular system. Hemizygous affected males die in the prenatal or perinatal period.^{[1] [2] [3] [4] [5]} Defects in FLNA are the cause of periventricular nodular heterotopia type 4 (PVNH4) [MIM:300537; also known as periventricular heterotopia Ehlers-Danlos variant. PVNH4 is characterized by nodular brain heterotopia, joint hypermobility and development of aortic dilation in early adulthood. Defects in FLNA are the cause of otopalatodigital syndrome type 1 (OPD1) [MIM:311300. OPD1 is an X-linked dominant multiple congenital anomalies disease mainly characterized by a generalized skeletal dysplasia, mild mental retardation, hearing loss, cleft palate, and typical facial anomalies. OPD1 belongs to a group of X-linked skeletal dysplasias known as oto-palato-digital syndrome spectrum disorders that also include OPD2, Melnick-Needles syndrome (MNS), and frontometaphyseal dysplasia (FMD). Remodeling of the cytoskeleton is central to the modulation of cell shape and migration. FLNA is a widely expressed protein that regulates re-organization of the actin cytoskeleton by interacting with integrins, transmembrane receptor complexes and second messengers. Males with OPD1 have cleft palate, malformations of the ossicles causing deafness and milder bone and limb defects than those associated with OPD2. Obligate female carriers of mutations causing both OPD1 and OPD2 have variable (often milder) expression of a similar phenotypic spectrum.^{[6] [7]} Defects in FLNA are the cause of otopalatodigital syndrome type 2 (OPD2) [MIM:304120; also known as cranioorodigital syndrome. OPD2 is a congenital bone disorder that is characterized by abnormally modeled, bowed bones, small or absent first digits and, more variably, cleft palate, posterior fossa brain anomalies, omphalocele and cardiac defects. Defects in FLNA are the cause of frontometaphyseal dysplasia (FMD) [MIM:305620. FMD is a congenital bone disease characterized by supraorbital hyperostosis, deafness and digital anomalies.^{[8] [9]} Defects in FLNA are the cause of Melnick-Needles syndrome (MNS) [MIM:309350. MNS is a severe congenital bone disorder characterized by typical facies (exophthalmos, full cheeks, micrognathia and malalignment of teeth), flaring of the metaphyses of long bones, s-like curvature of bones of legs, irregular constrictions in the ribs, and sclerosis of base of skull.^[10] Defects in FLNA are the cause of X-linked congenital idiopathic intestinal pseudoobstruction (CIIPX) [MIM:300048. CIIPX is characterized by a severe abnormality of gastrointestinal motility due to primary qualitative defects of enteric ganglia and nerve fibers. Affected individuals manifest recurrent signs of intestinal obstruction in the absence of any mechanical lesion.^[11] Defects in FLNA are the cause of FG syndrome type 2 (FGS2) [MIM:300321. FG syndrome (FGS) is an X-linked disorder characterized by mental retardation, relative macrocephaly, hypotonia and constipation.^[12] Defects in FLNA are the cause of terminal osseous dysplasia (TOD) [MIM:300244. A rare X-linked dominant male-lethal disease characterized by skeletal dysplasia of the limbs, pigmentary defects of the skin and recurrent digital fibroma during infancy. A significant phenotypic variability is observed in affected females.^[13] Defects in FLNA are the cause of cardiac valvular dysplasia X-linked (CVDX) [MIM:314400. A rare X-linked heart disease characterized by mitral and/or aortic valve regurgitation. The histologic features include fragmentation of collagenous bundles within the valve fibrosa and accumulation of proteoglycans, which produces excessive valve tissue leading to billowing of the valve leaflets.^[14] Note=Defects in FLNA may be a cause of macrothrombocytopenia, a disorder characterized by subnormal levels of blood platelets. Blood platelets are abonormally enlarged.ITA2B_HUMAN Defects in ITGA2B are a cause of Glanzmann thrombasthenia (GT) [MIM:273800; also known as thrombasthenia of Glanzmann and Naegeli. GT is the most common inherited disease of platelets. It is an autosomal recessive disorder characterized by mucocutaneous bleeding of mild-to-moderate severity and the inability of this integrin to recognize macromolecular or synthetic peptide ligands. GT has been classified clinically into types I and II. In type I, platelets show absence of the glycoprotein IIb/beta-3 complexes at their surface and lack fibrinogen and clot retraction capability. In type II, the platelets express the glycoprotein IIb/beta-3 complex at reduced levels (5-20% controls), have detectable amounts of fibrinogen, and have low or moderate clot retraction capability. The platelets of GT 'variants' have normal or near normal (60-100%) expression of dysfunctional receptors.^{[15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33]}

Function

FLNA_HUMAN Promotes orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. Anchors various transmembrane proteins to the actin cytoskeleton and serves as a scaffold for a wide range of cytoplasmic signaling proteins. Interaction with FLNA may allow neuroblast migration from the ventricular zone into the cortical plate. Tethers cell surface-localized furin, modulates its rate of internalization and directs its intracellular trafficking (By similarity). Involved in ciliogenesis.^[34] ITA2B_HUMAN Integrin alpha-IIb/beta-3 is a receptor for fibronectin, fibrinogen, plasminogen, prothrombin, thrombospondin and vitronectin. It recognizes the sequence R-G-D in a wide array of ligands. It recognizes the sequence H-H-L-G-G-G-A-K-Q-A-G-D-V in fibrinogen gamma chain. Following activation integrin alpha-IIb/beta-3 brings about platelet/platelet interaction through binding of soluble fibrinogen. This step leads to rapid platelet aggregation which physically plugs ruptured endothelial cell surface.

References

1. ↑ Hehr U, Hehr A, Uyanik G, Phelan E, Winkler J, Reardon W. A filamin A splice mutation resulting in a syndrome of facial dysmorphism, periventricular nodular heterotopia, and severe constipation reminiscent of cerebro-fronto-facial syndrome. J Med Genet. 2006 Jun;43(6):541-4. Epub 2005 Nov 18. PMID:16299064 doi:10.1136/jmg.2005.038505
2. ↑ Sheen VL, Dixon PH, Fox JW, Hong SE, Kinton L, Sisodiya SM, Duncan JS, Dubeau F, Scheffer IE, Schachter SC, Wilner A, Henchy R, Crino P, Kamuro K, DiMario F, Berg M, Kuzniecky R, Cole AJ, Bromfield E, Biber M, Schomer D, Wheless J, Silver K, Mochida GH, Berkovic SF, Andermann F, Andermann E, Dobyns WB, Wood NW, Walsh CA. Mutations in the X-linked filamin 1 gene cause periventricular nodular heterotopia in males as well as in females. Hum Mol Genet. 2001 Aug 15;10(17):1775-83. PMID:11532987
3. ↑ Kakita A, Hayashi S, Moro F, Guerrini R, Ozawa T, Ono K, Kameyama S, Walsh CA, Takahashi H. Bilateral periventricular nodular heterotopia due to filamin 1 gene mutation: widespread glomeruloid microvascular anomaly and dysplastic cytoarchitecture in the cerebral cortex. Acta Neuropathol. 2002 Dec;104(6):649-57. Epub 2002 Jul 23. PMID:12410386 doi:10.1007/s00401-002-0594-9
4. ↑ Moro F, Carrozzo R, Veggiotti P, Tortorella G, Toniolo D, Volzone A, Guerrini R. Familial periventricular heterotopia: missense and distal truncating mutations of the FLN1 gene. Neurology. 2002 Mar 26;58(6):916-21. PMID:11914408
5. ↑ Guerrini R, Mei D, Sisodiya S, Sicca F, Harding B, Takahashi Y, Dorn T, Yoshida A, Campistol J, Kramer G, Moro F, Dobyns WB, Parrini E. Germline and mosaic mutations of FLN1 in men with periventricular heterotopia. Neurology. 2004 Jul 13;63(1):51-6. PMID:15249610
6. ↑ Robertson SP, Twigg SR, Sutherland-Smith AJ, Biancalana V, Gorlin RJ, Horn D, Kenwrick SJ, Kim CA, Morava E, Newbury-Ecob R, Orstavik KH, Quarrell OW, Schwartz CE, Shears DJ, Suri M, Kendrick-Jones J, Wilkie AO. Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans. Nat Genet. 2003 Apr;33(4):487-91. Epub 2003 Mar 3. PMID:12612583 doi:10.1038/ng1119
7. ↑ Hidalgo-Bravo A, Pompa-Mera EN, Kofman-Alfaro S, Gonzalez-Bonilla CR, Zenteno JC. A novel filamin A D203Y mutation in a female patient with otopalatodigital type 1 syndrome and extremely skewed X chromosome inactivation. Am J Med Genet A. 2005 Jul 15;136(2):190-3. PMID:15940695 doi:10.1002/ajmg.a.30792
8. ↑ Robertson SP, Twigg SR, Sutherland-Smith AJ, Biancalana V, Gorlin RJ, Horn D, Kenwrick SJ, Kim CA, Morava E, Newbury-Ecob R, Orstavik KH, Quarrell OW, Schwartz CE, Shears DJ, Suri M, Kendrick-Jones J, Wilkie AO. Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans. Nat Genet. 2003 Apr;33(4):487-91. Epub 2003 Mar 3. PMID:12612583 doi:10.1038/ng1119
9. ↑ Zenker M, Nahrlich L, Sticht H, Reis A, Horn D. Genotype-epigenotype-phenotype correlations in females with frontometaphyseal dysplasia. Am J Med Genet A. 2006 May 15;140(10):1069-73. PMID:16596676 doi:10.1002/ajmg.a.31213
10. ↑ Robertson SP, Twigg SR, Sutherland-Smith AJ, Biancalana V, Gorlin RJ, Horn D, Kenwrick SJ, Kim CA, Morava E, Newbury-Ecob R, Orstavik KH, Quarrell OW, Schwartz CE, Shears DJ, Suri M, Kendrick-Jones J, Wilkie AO. Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans. Nat Genet. 2003 Apr;33(4):487-91. Epub 2003 Mar 3. PMID:12612583 doi:10.1038/ng1119
11. ↑ Gargiulo A, Auricchio R, Barone MV, Cotugno G, Reardon W, Milla PJ, Ballabio A, Ciccodicola A, Auricchio A. Filamin A is mutated in X-linked chronic idiopathic intestinal pseudo-obstruction with central nervous system involvement. Am J Hum Genet. 2007 Apr;80(4):751-8. Epub 2007 Feb 26. PMID:17357080 doi:S0002-9297(07)61110-0
12. ↑ Unger S, Mainberger A, Spitz C, Bahr A, Zeschnigk C, Zabel B, Superti-Furga A, Morris-Rosendahl DJ. Filamin A mutation is one cause of FG syndrome. Am J Med Genet A. 2007 Aug 15;143A(16):1876-9. PMID:17632775 doi:10.1002/ajmg.a.31751
13. ↑ Sun Y, Almomani R, Aten E, Celli J, van der Heijden J, Venselaar H, Robertson SP, Baroncini A, Franco B, Basel-Vanagaite L, Horii E, Drut R, Ariyurek Y, den Dunnen JT, Breuning MH. Terminal osseous dysplasia is caused by a single recurrent mutation in the FLNA gene. Am J Hum Genet. 2010 Jul 9;87(1):146-53. doi: 10.1016/j.ajhg.2010.06.008. PMID:20598277 doi:10.1016/j.ajhg.2010.06.008
14. ↑ Kyndt F, Gueffet JP, Probst V, Jaafar P, Legendre A, Le Bouffant F, Toquet C, Roy E, McGregor L, Lynch SA, Newbury-Ecob R, Tran V, Young I, Trochu JN, Le Marec H, Schott JJ. Mutations in the gene encoding filamin A as a cause for familial cardiac valvular dystrophy. Circulation. 2007 Jan 2;115(1):40-9. Epub 2006 Dec 26. PMID:17190868 doi:10.1161/CIRCULATIONAHA.106.622621
15. ↑ Poncz M, Rifat S, Coller BS, Newman PJ, Shattil SJ, Parrella T, Fortina P, Bennett JS. Glanzmann thrombasthenia secondary to a Gly273-->Asp mutation adjacent to the first calcium-binding domain of platelet glycoprotein IIb. J Clin Invest. 1994 Jan;93(1):172-9. PMID:8282784 doi:http://dx.doi.org/10.1172/JCI116942
16. ↑ Wilcox DA, Wautier JL, Pidard D, Newman PJ. A single amino acid substitution flanking the fourth calcium binding domain of alpha IIb prevents maturation of the alpha IIb beta 3 integrin complex. J Biol Chem. 1994 Feb 11;269(6):4450-7. PMID:7508443
17. ↑ Wilcox DA, Paddock CM, Lyman S, Gill JC, Newman PJ. Glanzmann thrombasthenia resulting from a single amino acid substitution between the second and third calcium-binding domains of GPIIb. Role of the GPIIb amino terminus in integrin subunit association. J Clin Invest. 1995 Apr;95(4):1553-60. PMID:7706461 doi:http://dx.doi.org/10.1172/JCI117828
18. ↑ Basani RB, Vilaire G, Shattil SJ, Kolodziej MA, Bennett JS, Poncz M. Glanzmann thrombasthenia due to a two amino acid deletion in the fourth calcium-binding domain of alpha IIb: demonstration of the importance of calcium-binding domains in the conformation of alpha IIb beta 3. Blood. 1996 Jul 1;88(1):167-73. PMID:8704171
19. ↑ French DL, Coller BS. Hematologically important mutations: Glanzmann thrombasthenia. Blood Cells Mol Dis. 1997;23(1):39-51. PMID:9215749 doi:10.1006/bcmd.1997.0117
20. ↑ Grimaldi CM, Chen F, Wu C, Weiss HJ, Coller BS, French DL. Glycoprotein IIb Leu214Pro mutation produces glanzmann thrombasthenia with both quantitative and qualitative abnormalities in GPIIb/IIIa. Blood. 1998 Mar 1;91(5):1562-71. PMID:9473221
21. ↑ Tadokoro S, Tomiyama Y, Honda S, Arai M, Yamamoto N, Shiraga M, Kosugi S, Kanakura Y, Kurata Y, Matsuzawa Y. A Gln747-->Pro substitution in the IIb subunit is responsible for a moderate IIbbeta3 deficiency in Glanzmann thrombasthenia. Blood. 1998 Oct 15;92(8):2750-8. PMID:9763559
22. ↑ Ambo H, Kamata T, Handa M, Kawai Y, Oda A, Murata M, Takada Y, Ikeda Y. Novel point mutations in the alphaIIb subunit (Phe289-->Ser, Glu324-->Lys and Gln747-->Pro) causing thrombasthenic phenotypes in four Japanese patients. Br J Haematol. 1998 Aug;102(3):829-40. PMID:9722314
23. ↑ Ruan J, Peyruchaud O, Alberio L, Valles G, Clemetson K, Bourre F, Nurden AT. Double heterozygosity of the GPIIb gene in a Swiss patient with Glanzmann's thrombasthenia. Br J Haematol. 1998 Sep;102(4):918-25. PMID:9734640
24. ↑ Gonzalez-Manchon C, Fernandez-Pinel M, Arias-Salgado EG, Ferrer M, Alvarez MV, Garcia-Munoz S, Ayuso MS, Parrilla R. Molecular genetic analysis of a compound heterozygote for the glycoprotein (GP) IIb gene associated with Glanzmann's thrombasthenia: disruption of the 674-687 disulfide bridge in GPIIb prevents surface exposure of GPIIb-IIIa complexes. Blood. 1999 Feb 1;93(3):866-75. PMID:9920835
25. ↑ Basani RB, French DL, Vilaire G, Brown DL, Chen F, Coller BS, Derrick JM, Gartner TK, Bennett JS, Poncz M. A naturally occurring mutation near the amino terminus of alphaIIb defines a new region involved in ligand binding to alphaIIbbeta3. Blood. 2000 Jan 1;95(1):180-8. PMID:10607701
26. ↑ Vinciguerra C, Bordet JC, Beaune G, Grenier C, Dechavanne M, Negrier C. Description of 10 new mutations in platelet glycoprotein IIb (alphaIIb) and glycoprotein IIIa (beta3) genes. Platelets. 2001 Dec;12(8):486-95. PMID:11798398 doi:10.1080/095371001317126383
27. ↑ Tanaka S, Hayashi T, Hori Y, Terada C, Han KS, Ahn HS, Bourre F, Tani Y. A Leu55 to Pro substitution in the integrin alphaIIb is responsible for a case of Glanzmann's thrombasthenia. Br J Haematol. 2002 Sep;118(3):833-5. PMID:12181054
28. ↑ D'Andrea G, Colaizzo D, Vecchione G, Grandone E, Di Minno G, Margaglione M. Glanzmann's thrombasthenia: identification of 19 new mutations in 30 patients. Thromb Haemost. 2002 Jun;87(6):1034-42. PMID:12083483
29. ↑ Mitchell WB, Li JH, Singh F, Michelson AD, Bussel J, Coller BS, French DL. Two novel mutations in the alpha IIb calcium-binding domains identify hydrophobic regions essential for alpha IIbbeta 3 biogenesis. Blood. 2003 Mar 15;101(6):2268-76. Epub 2002 Nov 7. PMID:12424194 doi:10.1182/blood-2002-07-2266
30. ↑ Kiyoi T, Tomiyama Y, Honda S, Tadokoro S, Arai M, Kashiwagi H, Kosugi S, Kato H, Kurata Y, Matsuzawa Y. A naturally occurring Tyr143His alpha IIb mutation abolishes alpha IIb beta 3 function for soluble ligands but retains its ability for mediating cell adhesion and clot retraction: comparison with other mutations causing ligand-binding defects. Blood. 2003 May 1;101(9):3485-91. Epub 2002 Dec 27. PMID:12506038 doi:10.1182/blood-2002-07-2144
31. ↑ Nurden AT, Breillat C, Jacquelin B, Combrie R, Freedman J, Blanchette VS, Schmugge M, Rand ML. Triple heterozygosity in the integrin alphaIIb subunit in a patient with Glanzmann's thrombasthenia. J Thromb Haemost. 2004 May;2(5):813-9. PMID:15099289 doi:10.1046/j.1538-7836.2004.00711.x
32. ↑ Rosenberg N, Landau M, Luboshitz J, Rechavi G, Seligsohn U. A novel Phe171Cys mutation in integrin alpha causes Glanzmann thrombasthenia by abrogating alphabeta complex formation. J Thromb Haemost. 2004 Jul;2(7):1167-75. PMID:15219201 doi:10.1111/j.1538-7836.2004.00758.x
33. ↑ Jayo A, Pabon D, Lastres P, Jimenez-Yuste V, Gonzalez-Manchon C. Type II Glanzmann thrombasthenia in a compound heterozygote for the alpha IIb gene. A novel missense mutation in exon 27. Haematologica. 2006 Oct;91(10):1352-9. PMID:17018384
34. ↑ Adams M, Simms RJ, Abdelhamed Z, Dawe HR, Szymanska K, Logan CV, Wheway G, Pitt E, Gull K, Knowles MA, Blair E, Cross SH, Sayer JA, Johnson CA. A meckelin-filamin A interaction mediates ciliogenesis. Hum Mol Genet. 2012 Mar 15;21(6):1272-86. doi: 10.1093/hmg/ddr557. Epub 2011 Nov , 25. PMID:22121117 doi:10.1093/hmg/ddr557