8rnu

Structural highlights

Disease

ITM2B_HUMAN Retinal dystrophy with inner retinal dysfunction and ganglion cell anomalies;ADan amyloidosis;ABri amyloidosis. The disease is caused by variants affecting the gene represented in this entry. A single base substitution at the stop codon of ITM2B generates a 277-residue precursor that is cleaved at the normal furin processing site to generate the ABri amyloidogenic peptide (PubMed:10391242). ABri accumulates in the brain and produces amyloid fibrils responsible for neuronal dysfunction and dementia. ABri peptide variant forms fibrils in vitro (PubMed:10526337).^{[1] [2]} The disease is caused by variants affecting the gene represented in this entry. A decamer duplication in the 3' region of ITM2B results in the production of the ADan amyloidogenic peptide (PubMed:10781099). ADan is generated by cleavage of the mutated precursor at the normal furin processing site. ADan accumulates in the brain and produces amyloid fibrils responsible for neuronal dysfunction and dementia.^[3] The disease is caused by variants affecting the gene represented in this entry.

Function

ITM2B_HUMAN Plays a regulatory role in the processing of the amyloid-beta A4 precursor protein (APP) and acts as an inhibitor of the amyloid-beta peptide aggregation and fibrils deposition. Plays a role in the induction of neurite outgrowth. Functions as a protease inhibitor by blocking access of secretases to APP cleavage sites. Mature BRI2 (mBRI2) functions as a modulator of the amyloid-beta A4 precursor protein (APP) processing leading to a strong reduction in the secretion of secretase-processed amyloid-beta protein 40 and amyloid-beta protein 42. Bri23 peptide prevents aggregation of APP amyloid-beta protein 42 into toxic oligomers.

References

1. ↑ Vidal R, Frangione B, Rostagno A, Mead S, Révész T, Plant G, Ghiso J. A stop-codon mutation in the BRI gene associated with familial British dementia. Nature. 1999 Jun 24;399(6738):776-81. PMID:10391242 doi:10.1038/21637
2. ↑ Kim SH, Wang R, Gordon DJ, Bass J, Steiner DF, Lynn DG, Thinakaran G, Meredith SC, Sisodia SS. Furin mediates enhanced production of fibrillogenic ABri peptides in familial British dementia. Nat Neurosci. 1999 Nov;2(11):984-8. PMID:10526337 doi:10.1038/14783
3. ↑ Vidal R, Revesz T, Rostagno A, Kim E, Holton JL, Bek T, Bojsen-Møller M, Braendgaard H, Plant G, Ghiso J, Frangione B. A decamer duplication in the 3' region of the BRI gene originates an amyloid peptide that is associated with dementia in a Danish kindred. Proc Natl Acad Sci U S A. 2000 Apr 25;97(9):4920-5. PMID:10781099 doi:10.1073/pnas.080076097