| Structural highlights
Disease
[BGH3_HUMAN] Defects in TGFBI are the cause of epithelial basement membrane corneal dystrophy (EBMD) [MIM:121820]; also known as Cogan corneal dystrophy or map-dot-fingerprint type corneal dystrophy. EBMD is a bilateral anterior corneal dystrophy characterized by grayish epithelial fingerprint lines, geographic map-like lines, and dots (or microcysts) on slit-lamp examination. Pathologic studies show abnormal, redundant basement membrane and intraepithelial lacunae filled with cellular debris. Although this disorder usually is not considered to be inherited, families with autosomal dominant inheritance have been identified.[1] Defects in TGFBI are the cause of corneal dystrophy Groenouw type 1 (CDGG1) [MIM:121900]; also known as corneal dystrophy granular type. Inheritance is autosomal dominant. Corneal dystrophies show progressive opacification of the cornea leading to severe visual handicap.[2] Defects in TGFBI are the cause of corneal dystrophy lattice type 1 (CDL1) [MIM:122200]. Inheritance is autosomal dominant. Defects in TGFBI are a cause of corneal dystrophy Thiel-Behnke type (CDTB) [MIM:602082]; also known as corneal dystrophy of Bowman layer type 2 (CDB2). Defects in TGFBI are the cause of Reis-Buecklers corneal dystrophy (CDRB) [MIM:608470]; also known as corneal dystrophy of Bowman layer type 1 (CDB1).[3] [4] [5] Defects in TGFBI are the cause of lattice corneal dystrophy type 3A (CDL3A) [MIM:608471]. CDL3A clinically resembles to lattice corneal dystrophy type 3, but differs in that its age of onset is 70 to 90 years. It has an autosomal dominant inheritance pattern.[6] [7] Defects in TGFBI are the cause of Avellino corneal dystrophy (ACD) [MIM:607541]. ACD could be considered a variant of granular dystrophy with a significant amyloidogenic tendency. Inheritance is autosomal dominant.
Function
[BGH3_HUMAN] Binds to type I, II, and IV collagens. This adhesion protein may play an important role in cell-collagen interactions. In cartilage, may be involved in endochondral bone formation.
Publication Abstract from PubMed
A major cause of visual impairment, corneal dystrophies result from accumulation of protein deposits in the cornea. One of the proteins involved is transforming growth factor beta-induced protein (TGFBIp), an extracellular matrix component that interacts with integrins but also produces corneal deposits when mutated. Human TGFBIp is a multi-domain 683-residue protein, which contains one CROPT domain and four FAS1 domains. Its structure spans approximately 120 A and reveals that vicinal domains FAS1-1/FAS1-2 and FAS1-3/FAS1-4 tightly interact in an equivalent manner. The FAS1 domains are sandwiches of two orthogonal four-stranded beta sheets decorated with two three-helix insertions. The N-terminal FAS1 dimer forms a compact moiety with the structurally novel CROPT domain, which is a five-stranded all-beta cysteine-knot solely found in TGFBIp and periostin. The overall TGFBIp architecture discloses regions for integrin binding and that most dystrophic mutations cluster at both molecule ends, within domains FAS1-1 and FAS1-4.
Structural and Functional Implications of Human Transforming Growth Factor beta-Induced Protein, TGFBIp, in Corneal Dystrophies.,Garcia-Castellanos R, Nielsen NS, Runager K, Thogersen IB, Lukassen MV, Poulsen ET, Goulas T, Enghild JJ, Gomis-Ruth FX Structure. 2017 Sep 27. pii: S0969-2126(17)30292-7. doi:, 10.1016/j.str.2017.09.001. PMID:28988748[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Boutboul S, Black GC, Moore JE, Sinton J, Menasche M, Munier FL, Laroche L, Abitbol M, Schorderet DF. A subset of patients with epithelial basement membrane corneal dystrophy have mutations in TGFBI/BIGH3. Hum Mutat. 2006 Jun;27(6):553-7. PMID:16652336 doi:10.1002/humu.20331
- ↑ Chakravarthi SV, Kannabiran C, Sridhar MS, Vemuganti GK. TGFBI gene mutations causing lattice and granular corneal dystrophies in Indian patients. Invest Ophthalmol Vis Sci. 2005 Jan;46(1):121-5. PMID:15623763 doi:46/1/121
- ↑ Chakravarthi SV, Kannabiran C, Sridhar MS, Vemuganti GK. TGFBI gene mutations causing lattice and granular corneal dystrophies in Indian patients. Invest Ophthalmol Vis Sci. 2005 Jan;46(1):121-5. PMID:15623763 doi:46/1/121
- ↑ Okada M, Yamamoto S, Tsujikawa M, Watanabe H, Inoue Y, Maeda N, Shimomura Y, Nishida K, Quantock AJ, Kinoshita S, Tano Y. Two distinct kerato-epithelin mutations in Reis-Bucklers corneal dystrophy. Am J Ophthalmol. 1998 Oct;126(4):535-42. PMID:9780098
- ↑ Rozzo C, Fossarello M, Galleri G, Sole G, Serru A, Orzalesi N, Serra A, Pirastu M. A common beta ig-h3 gene mutation (delta f540) in a large cohort of Sardinian Reis Bucklers corneal dystrophy patients. Mutations in brief no. 180. Online. Hum Mutat. 1998;12(3):215-6. PMID:10660331
- ↑ Yamamoto S, Okada M, Tsujikawa M, Shimomura Y, Nishida K, Inoue Y, Watanabe H, Maeda N, Kurahashi H, Kinoshita S, Nakamura Y, Tano Y. A kerato-epithelin (betaig-h3) mutation in lattice corneal dystrophy type IIIA. Am J Hum Genet. 1998 Mar;62(3):719-22. PMID:9497262 doi:10.1086/301765
- ↑ Stix B, Leber M, Bingemer P, Gross C, Ruschoff J, Fandrich M, Schorderet DF, Vorwerk CK, Zacharias M, Roessner A, Rocken C. Hereditary lattice corneal dystrophy is associated with corneal amyloid deposits enclosing C-terminal fragments of keratoepithelin. Invest Ophthalmol Vis Sci. 2005 Apr;46(4):1133-9. PMID:15790870 doi:46/4/1133
- ↑ Garcia-Castellanos R, Nielsen NS, Runager K, Thogersen IB, Lukassen MV, Poulsen ET, Goulas T, Enghild JJ, Gomis-Ruth FX. Structural and Functional Implications of Human Transforming Growth Factor beta-Induced Protein, TGFBIp, in Corneal Dystrophies. Structure. 2017 Sep 27. pii: S0969-2126(17)30292-7. doi:, 10.1016/j.str.2017.09.001. PMID:28988748 doi:http://dx.doi.org/10.1016/j.str.2017.09.001
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