1jb3

Structural highlights

Function

[AGRIN_CHICK] Isoform 1: heparan sulfate basal lamina glycoprotein that plays a central role in the formation and the maintenance of the neuromuscular junction (NMJ) and directs key events in postsynaptic differentiation. Component of the AGRN-LRP4 receptor complex that induces the phosphorylation and activation of MUSK. The activation of MUSK in myotubes induces the formation of NMJ by regulating different processes including the transcription of specific genes and the clustering of AChR in the postsynaptic membrane. Calcium ions are required for maximal AChR clustering. AGRN funtion in neurons is highly regulated by alternative splicing, glycan binding and proteolytic processing. Modulates calcium ion homestasis in neurons, specifically by inducing an increase in cytoplasmic calcium ions. Functions differentially in the central nervous system (CNS) by inhibiting the alpha(3)-subtype of Na+/K+-ATPase and evoking depolarization at CNS synapses.^{[1] [2] [3] [4] [5] [6] [7]} Isoform 9: transmembrane agrin (TM-agrin), the predominant form in neurons of the brain, induces dendritic filopodia and synapse formation in mature hippocampal neurons in large part due to the attached glycosaminoglycan chains and the action of Rho-family GTPases.^{[8] [9] [10] [11] [12] [13] [14]} Isoform 2, isoform 4 and isoform 7: muscle agrin isoforms, which lack the 8-amino acid insert at the 'B' site, but with the insert at the'A' site have no AChr clustering activity nor MUSK activation but bind heparin. Bind alpha-dystroglycan with lower affinity.^{[15] [16] [17] [18] [19] [20] [21]} Isoform 5: muscle agrin A0B0 lacking inserts at both 'A' and 'B' sites has no heparin-binding nor AChR clustering activity but binds strongly alpha-dystroglycan.^{[22] [23] [24] [25] [26] [27] [28]} Agrin N-terminal 110 kDa subunit: is involved in modulation of growth factor signaling (By similarity). Involved also in the regulation of neurite outgrowth probably due to the presence of the glycosaminoglcan (GAG) side chains of heparan and chondroitin sulfate attached to the Ser/Thr- and Gly/Ser-rich regions. Also involved in modulation of growth factor signaling.^{[29] [30] [31] [32] [33] [34] [35]} Agrin C-terminal 22 kDa fragment: this released fragment is important for agrin signaling and to exert a maximal dendritic filopodia-inducing effect. All 'B' splice variants of this fragment also show an increase in the number of filopodia.^{[36] [37] [38] [39] [40] [41] [42]}

See Also

• Agrin

References

1. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
2. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
3. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
4. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
5. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
6. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
7. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
8. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
9. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
10. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
11. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
12. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
13. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
14. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
15. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
16. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
17. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
18. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
19. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
20. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
21. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
22. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
23. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
24. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
25. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
26. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
27. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
28. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
29. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
30. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
31. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
32. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
33. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
34. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
35. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
36. ↑ Gesemann M, Denzer AJ, Ruegg MA. Acetylcholine receptor-aggregating activity of agrin isoforms and mapping of the active site. J Cell Biol. 1995 Feb;128(4):625-36. PMID:7860635
37. ↑ Bezakova G, Helm JP, Francolini M, Lomo T. Effects of purified recombinant neural and muscle agrin on skeletal muscle fibers in vivo. J Cell Biol. 2001 Jun 25;153(7):1441-52. PMID:11425874
38. ↑ Baerwald-de la Torre K, Winzen U, Halfter W, Bixby JL. Glycosaminoglycan-dependent and -independent inhibition of neurite outgrowth by agrin. J Neurochem. 2004 Jul;90(1):50-61. PMID:15198666 doi:http://dx.doi.org/10.1111/j.1471-4159.2004.02454.x
39. ↑ Scotton P, Bleckmann D, Stebler M, Sciandra F, Brancaccio A, Meier T, Stetefeld J, Ruegg MA. Activation of muscle-specific receptor tyrosine kinase and binding to dystroglycan are regulated by alternative mRNA splicing of agrin. J Biol Chem. 2006 Dec 1;281(48):36835-45. Epub 2006 Sep 29. PMID:17012237 doi:http://dx.doi.org/10.1074/jbc.M607887200
40. ↑ Sallum CO, Kammerer RA, Alexandrescu AT. Thermodynamic and structural studies of carbohydrate binding by the agrin-G3 domain. Biochemistry. 2007 Aug 21;46(33):9541-50. Epub 2007 Jul 25. PMID:17649979 doi:http://dx.doi.org/10.1021/bi7006383
41. ↑ Porten E, Seliger B, Schneider VA, Woll S, Stangel D, Ramseger R, Kroger S. The process-inducing activity of transmembrane agrin requires follistatin-like domains. J Biol Chem. 2010 Jan 29;285(5):3114-25. doi: 10.1074/jbc.M109.039420. Epub 2009 , Nov 25. PMID:19940118 doi:http://dx.doi.org/10.1074/jbc.M109.039420
42. ↑ Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One. 2012;7(9):e43669. doi: 10.1371/journal.pone.0043669. Epub 2012 Sep 11. PMID:22984437 doi:http://dx.doi.org/10.1371/journal.pone.0043669
43. ↑ Stetefeld J, Jenny M, Schulthess T, Landwehr R, Schumacher B, Frank S, Ruegg MA, Engel J, Kammerer RA. The laminin-binding domain of agrin is structurally related to N-TIMP-1. Nat Struct Biol. 2001 Aug;8(8):705-9. PMID:11473262 doi:10.1038/90422