3i70 | pdb_00003i70

Long-wavelength structure of NtA

spinqualitylabelsall models 3i70, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3i70 is a 1 chain structure with sequence from Chick. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1pxu Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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. 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. 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. 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. 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. 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. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Agrin is a multidomain heparan sulfate proteoglycan involved in postsynaptic differentiation at the neuromuscular junction. Binding of agrin to synaptic basal lamina is mediated by the N-terminal agrin (NtA) domain. The NtA domain of agrin is followed by a tandem of nine follistatin-like (FS) domains forming a rod-like spacer to the laminin G-like domains of the molecule. Here we report that the most C-terminal cysteine residue of NtA (Cys123) forms an interdomain disulfide bond with the FOLN subdomain of the FS module. Remarkably, this single cysteine is flanked by Leu117 and Val124, which are two essential beta-branched amino acids forming the heterocomplex of NtA with the gamma 1 chain of laminin. Moreover, we show that this covalent linkage compensates for the seven amino acid residue splice insert at the very C-terminal helix H3 and causes a rigid interface between NtA and FS independent of the alternative mRNA splice event. These results suggest that the interdomain disulfide bond between the NtA and the first FS domain might be important for the proper folding of agrin. An interdomain disulfide bridge links the NtA and first FS domain in agrin.,McFarlane AA, Stetefeld J Protein Sci. 2009 Dec;18(12):2421-8. PMID:19845005 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Agrin

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