1eg4

Structural highlights

Disease

[DAG1_HUMAN] Defects in DAG1 are the cause of muscular dystrophy-dystroglycanopathy limb-girdle type C7 (MDDGC7) [MIM:613818]. An autosomal recessive muscular dystrophy showing onset in early childhood, and associated with mental retardation without structural brain anomalies. Note=MDDGC7 is caused by DAG1 mutations that interfere with normal post-translational processing, resulting in defective DAG1 glycosylation and impaired interactions with extracellular-matrix components. Other muscular dystrophy-dystroglycanopathies are caused by defects in enzymes involved in protein O-glycosylation.^[1] [DMD_HUMAN] Defects in DMD are the cause of Duchenne muscular dystrophy (DMD) [MIM:310200]. DMD is the most common form of muscular dystrophy; a sex-linked recessive disorder. It typically presents in boys aged 3 to 7 year as proximal muscle weakness causing waddling gait, toe-walking, lordosis, frequent falls, and difficulty in standing up and climbing up stairs. The pelvic girdle is affected first, then the shoulder girdle. Progression is steady and most patients are confined to a wheelchair by age of 10 or 12. Flexion contractures and scoliosis ultimately occur. About 50% of patients have a lower IQ than their genetic expectations would suggest. There is no treatment.^{[2] [3] [4] [5]} Defects in DMD are the cause of Becker muscular dystrophy (BMD) [MIM:300376]. BMD resembles DMD in hereditary and clinical features but is later in onset and more benign.^[6] Defects in DMD are a cause of cardiomyopathy dilated X-linked type 3B (CMD3B) [MIM:302045]; also known as X-linked dilated cardiomyopathy (XLCM). Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.^{[7] [8] [9]}

Function

[DAG1_HUMAN] The dystroglycan complex is involved in a number of processes including laminin and basement membrane assembly, sarcolemmal stability, cell survival, peripheral nerve myelination, nodal structure, cell migration, and epithelial polarization.^{[10] [11] [12] [13]} Alpha-dystroglycan is an extracellular peripheral glycoprotein that acts as a receptor for both extracellular matrix proteins containing laminin-G domains, and for certain adenoviruses. Receptor for laminin-2 (LAMA2) and agrin in peripheral nerve Schwann cells. Also acts as a receptor for M.leprae in peripheral nerve Schwann cells but only in the presence of the G-domain of LAMA2, and for lymphocytic choriomeningitis virus, Old World Lassa fever virus, and clade C New World arenaviruses.^{[14] [15] [16] [17]} Beta-dystroglycan is a transmembrane protein that plays important roles in connecting the extracellular matrix to the cytoskeleton. Acts as a cell adhesion receptor in both muscle and non-muscle tissues. Receptor for both DMD and UTRN and, through these interactions, scaffolds axin to the cytoskeleton. Also functions in cell adhesion-mediated signaling and implicated in cell polarity.^{[18] [19] [20] [21]} [DMD_HUMAN] Anchors the extracellular matrix to the cytoskeleton via F-actin. Ligand for dystroglycan. Component of the dystrophin-associated glycoprotein complex which accumulates at the neuromuscular junction (NMJ) and at a variety of synapses in the peripheral and central nervous systems and has a structural function in stabilizing the sarcolemma. Also implicated in signaling events and synaptic transmission.^[22]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

• Dystrophin

References

1. ↑ Hara Y, Balci-Hayta B, Yoshida-Moriguchi T, Kanagawa M, Beltran-Valero de Bernabe D, Gundesli H, Willer T, Satz JS, Crawford RW, Burden SJ, Kunz S, Oldstone MB, Accardi A, Talim B, Muntoni F, Topaloglu H, Dincer P, Campbell KP. A dystroglycan mutation associated with limb-girdle muscular dystrophy. N Engl J Med. 2011 Mar 10;364(10):939-46. doi: 10.1056/NEJMoa1006939. PMID:21388311 doi:10.1056/NEJMoa1006939
2. ↑ Prior TW, Papp AC, Snyder PJ, Burghes AH, Bartolo C, Sedra MS, Western LM, Mendell JR. A missense mutation in the dystrophin gene in a Duchenne muscular dystrophy patient. Nat Genet. 1993 Aug;4(4):357-60. PMID:8401582 doi:http://dx.doi.org/10.1038/ng0893-357
3. ↑ Prior TW, Bartolo C, Papp AC, Snyder PJ, Sedra MS, Burghes AH, Mendell JR. Identification of a missense mutation, single base deletion and a polymorphism in the dystrophin exon 16. Hum Mol Genet. 1994 Jul;3(7):1173-4. PMID:7981690
4. ↑ Lenk U, Oexle K, Voit T, Ancker U, Hellner KA, Speer A, Hubner C. A cysteine 3340 substitution in the dystroglycan-binding domain of dystrophin associated with Duchenne muscular dystrophy, mental retardation and absence of the ERG b-wave. Hum Mol Genet. 1996 Jul;5(7):973-5. PMID:8817332
5. ↑ Goldberg LR, Hausmanowa-Petrusewicz I, Fidzianska A, Duggan DJ, Steinberg LS, Hoffman EP. A dystrophin missense mutation showing persistence of dystrophin and dystrophin-associated proteins yet a severe phenotype. Ann Neurol. 1998 Dec;44(6):971-6. PMID:9851445 doi:10.1002/ana.410440619
6. ↑ Eraslan S, Kayserili H, Apak MY, Kirdar B. Identification of point mutations in Turkish DMD/BMD families using multiplex-single stranded conformation analysis (SSCA). Eur J Hum Genet. 1999 Oct-Nov;7(7):765-70. PMID:10573008 doi:10.1038/sj.ejhg.5200370
7. ↑ Ortiz-Lopez R, Li H, Su J, Goytia V, Towbin JA. Evidence for a dystrophin missense mutation as a cause of X-linked dilated cardiomyopathy. Circulation. 1997 May 20;95(10):2434-40. PMID:9170407
8. ↑ Feng J, Yan JY, Buzin CH, Sommer SS, Towbin JA. Comprehensive mutation scanning of the dystrophin gene in patients with nonsyndromic X-linked dilated cardiomyopathy. J Am Coll Cardiol. 2002 Sep 18;40(6):1120-4. PMID:12354438
9. ↑ Feng J, Yan J, Buzin CH, Towbin JA, Sommer SS. Mutations in the dystrophin gene are associated with sporadic dilated cardiomyopathy. Mol Genet Metab. 2002 Sep-Oct;77(1-2):119-26. PMID:12359139
10. ↑ Rambukkana A, Yamada H, Zanazzi G, Mathus T, Salzer JL, Yurchenco PD, Campbell KP, Fischetti VA. Role of alpha-dystroglycan as a Schwann cell receptor for Mycobacterium leprae. Science. 1998 Dec 11;282(5396):2076-9. PMID:9851927
11. ↑ Sotgia F, Lee H, Bedford MT, Petrucci T, Sudol M, Lisanti MP. Tyrosine phosphorylation of beta-dystroglycan at its WW domain binding motif, PPxY, recruits SH2 domain containing proteins. Biochemistry. 2001 Dec 4;40(48):14585-92. PMID:11724572
12. ↑ Imperiali M, Thoma C, Pavoni E, Brancaccio A, Callewaert N, Oxenius A. O Mannosylation of alpha-dystroglycan is essential for lymphocytic choriomeningitis virus receptor function. J Virol. 2005 Nov;79(22):14297-308. PMID:16254364 doi:10.1128/JVI.79.22.14297-14308.2005
13. ↑ Rojek JM, Spiropoulou CF, Campbell KP, Kunz S. Old World and clade C New World arenaviruses mimic the molecular mechanism of receptor recognition used by alpha-dystroglycan's host-derived ligands. J Virol. 2007 Jun;81(11):5685-95. Epub 2007 Mar 14. PMID:17360738 doi:10.1128/JVI.02574-06
14. ↑ Rambukkana A, Yamada H, Zanazzi G, Mathus T, Salzer JL, Yurchenco PD, Campbell KP, Fischetti VA. Role of alpha-dystroglycan as a Schwann cell receptor for Mycobacterium leprae. Science. 1998 Dec 11;282(5396):2076-9. PMID:9851927
15. ↑ Sotgia F, Lee H, Bedford MT, Petrucci T, Sudol M, Lisanti MP. Tyrosine phosphorylation of beta-dystroglycan at its WW domain binding motif, PPxY, recruits SH2 domain containing proteins. Biochemistry. 2001 Dec 4;40(48):14585-92. PMID:11724572
16. ↑ Imperiali M, Thoma C, Pavoni E, Brancaccio A, Callewaert N, Oxenius A. O Mannosylation of alpha-dystroglycan is essential for lymphocytic choriomeningitis virus receptor function. J Virol. 2005 Nov;79(22):14297-308. PMID:16254364 doi:10.1128/JVI.79.22.14297-14308.2005
17. ↑ Rojek JM, Spiropoulou CF, Campbell KP, Kunz S. Old World and clade C New World arenaviruses mimic the molecular mechanism of receptor recognition used by alpha-dystroglycan's host-derived ligands. J Virol. 2007 Jun;81(11):5685-95. Epub 2007 Mar 14. PMID:17360738 doi:10.1128/JVI.02574-06
18. ↑ Rambukkana A, Yamada H, Zanazzi G, Mathus T, Salzer JL, Yurchenco PD, Campbell KP, Fischetti VA. Role of alpha-dystroglycan as a Schwann cell receptor for Mycobacterium leprae. Science. 1998 Dec 11;282(5396):2076-9. PMID:9851927
19. ↑ Sotgia F, Lee H, Bedford MT, Petrucci T, Sudol M, Lisanti MP. Tyrosine phosphorylation of beta-dystroglycan at its WW domain binding motif, PPxY, recruits SH2 domain containing proteins. Biochemistry. 2001 Dec 4;40(48):14585-92. PMID:11724572
20. ↑ Imperiali M, Thoma C, Pavoni E, Brancaccio A, Callewaert N, Oxenius A. O Mannosylation of alpha-dystroglycan is essential for lymphocytic choriomeningitis virus receptor function. J Virol. 2005 Nov;79(22):14297-308. PMID:16254364 doi:10.1128/JVI.79.22.14297-14308.2005
21. ↑ Rojek JM, Spiropoulou CF, Campbell KP, Kunz S. Old World and clade C New World arenaviruses mimic the molecular mechanism of receptor recognition used by alpha-dystroglycan's host-derived ligands. J Virol. 2007 Jun;81(11):5685-95. Epub 2007 Mar 14. PMID:17360738 doi:10.1128/JVI.02574-06
22. ↑ Haenggi T, Fritschy JM. Role of dystrophin and utrophin for assembly and function of the dystrophin glycoprotein complex in non-muscle tissue. Cell Mol Life Sci. 2006 Jul;63(14):1614-31. PMID:16710609 doi:10.1007/s00018-005-5461-0
23. ↑ Huang X, Poy F, Zhang R, Joachimiak A, Sudol M, Eck MJ. Structure of a WW domain containing fragment of dystrophin in complex with beta-dystroglycan. Nat Struct Biol. 2000 Aug;7(8):634-8. PMID:10932245 doi:10.1038/77923