Agrin - P25304 (AGRIN_RAT)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for P25304: 2
 
Function
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. This neuron-specific (z+) isoform is a 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 function in neurons is highly regulated by alternative splicing, glycan binding and proteolytic processing. Modulates calcium ion homeostasis 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. This transmembrane agrin (TM-agrin) isoform, the predominate 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. UniProt
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Subunit Structure
Monomer. Component of the AGRN-LRP4 complex that consists of a tetramer of two AGRN-LRP4 heterodimers. Interacts (via the laminin G-like 3 domain) directly with LRP4; the interaction is required for activation of MUSK and clustering of AChR and requires the 'z8' insert present in the z(+8) isoforms. Interacts (N-terminal subunit) with TGF-beta family members, BMP2 AND BMP4; the interactions inhibit the activity of these growth factors. Interacts with TGFB1; the interaction enhances the activity of TGFB1. Interacts with DAG1; the interaction is influenced by cell surface glycosaminoglycans and by alternative splicing of AGRN. UniProt
Domain
Both laminin G-like 2 (G2) and laminin G-like 3 (G3) domains are required for alpha-dystroglycan binding. G3 domain is required for C-terminal heparin, heparan sulfate and sialic acid binding. UniProt
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